diff --git a/PKHeX.Core/Editing/Applicators/TechnicalRecordApplicator.cs b/PKHeX.Core/Editing/Applicators/TechnicalRecordApplicator.cs
index cbb18af8f..af452d48d 100644
--- a/PKHeX.Core/Editing/Applicators/TechnicalRecordApplicator.cs
+++ b/PKHeX.Core/Editing/Applicators/TechnicalRecordApplicator.cs
@@ -124,10 +124,12 @@ public static void SetRecordFlagsAll(this ITechRecord pk, ReadOnlySpan<EvoCriter
         _ => false,
     };
 
+    /// <inheritdoc cref="SetRecordFlags(ITechRecord, PKM, TechnicalRecordApplicatorOption, LegalityAnalysis)"/>
     public static void SetRecordFlags<T>(this T pk, TechnicalRecordApplicatorOption option)
         where T : PKM, ITechRecord
         => SetRecordFlags(pk, pk, option);
 
+    /// <inheritdoc cref="SetRecordFlags(ITechRecord, PKM, TechnicalRecordApplicatorOption, LegalityAnalysis)"/>
     public static void SetRecordFlags(this ITechRecord record, PKM pk, TechnicalRecordApplicatorOption option)
     {
         record.ClearRecordFlags();
@@ -142,6 +144,13 @@ public static void SetRecordFlags(this ITechRecord record, PKM pk, TechnicalReco
         SetRecordFlagsInternal(record, pk, option, la);
     }
 
+    /// <summary>
+    /// Applies the Technical Record flags based on the <see cref="option"/>.
+    /// </summary>
+    /// <param name="record">Object to apply to.</param>
+    /// <param name="pk">Object to apply to, but base type for other logic.</param>
+    /// <param name="option">Option to apply.</param>
+    /// <param name="la">Legality analysis to use for the option.</param>
     public static void SetRecordFlags(this ITechRecord record, PKM pk, TechnicalRecordApplicatorOption option, LegalityAnalysis la)
     {
         record.ClearRecordFlags();
@@ -172,10 +181,28 @@ private static void SetRecordFlagsInternal(ITechRecord record, PKM pk, Technical
     }
 }
 
+/// <summary>
+/// Options for applying Technical Record flags.
+/// </summary>
 public enum TechnicalRecordApplicatorOption
 {
+    /// <summary>
+    /// Do not apply any flags. Clear all flags.
+    /// </summary>
     None,
+
+    /// <summary>
+    /// Apply all flags, regardless of legality.
+    /// </summary>
     ForceAll,
+
+    /// <summary>
+    /// Apply legal flags based on the current moves.
+    /// </summary>
     LegalCurrent,
+
+    /// <summary>
+    /// Apply legal flags based on all moves able to learn in the game it resides in.
+    /// </summary>
     LegalAll,
 }
diff --git a/PKHeX.Core/Editing/Database/TrainerDatabase.cs b/PKHeX.Core/Editing/Database/TrainerDatabase.cs
index eb4c10f69..2758fb1cc 100644
--- a/PKHeX.Core/Editing/Database/TrainerDatabase.cs
+++ b/PKHeX.Core/Editing/Database/TrainerDatabase.cs
@@ -1,5 +1,7 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.InteropServices;
 
 namespace PKHeX.Core;
 
@@ -25,17 +27,12 @@ public sealed class TrainerDatabase
             return GetTrainerFromGroup(version, language);
 
         if (Database.TryGetValue(version, out var list))
-            return GetRandomChoice(list);
+            return list[GetRandomIndex(list.Count)];
 
         return null;
     }
 
-    private static T GetRandomChoice<T>(IReadOnlyList<T> list)
-    {
-        if (list.Count == 1)
-            return list[0];
-        return list[Util.Rand.Next(list.Count)];
-    }
+    private static int GetRandomIndex(int count) => count == 1 ? 0 : Util.Rand.Next(count);
 
     /// <summary>
     /// Fetches an appropriate trainer based on the requested <see cref="version"/> group.
@@ -57,7 +54,8 @@ private static T GetRandomChoice<T>(IReadOnlyList<T> list)
                 return new KeyValuePair<GameVersion, List<ITrainerInfo>>(z.Key, filtered);
             }).Where(z => z.Value.Count != 0).ToList();
         }
-        return GetRandomTrainer(possible);
+        var span = CollectionsMarshal.AsSpan(possible);
+        return GetRandomTrainer(span);
     }
 
     /// <summary>
@@ -80,15 +78,17 @@ private static T GetRandomChoice<T>(IReadOnlyList<T> list)
                 return new KeyValuePair<GameVersion, List<ITrainerInfo>>(z.Key, filtered);
             }).Where(z => z.Value.Count != 0).ToList();
         }
-        return GetRandomTrainer(possible);
+        var span = CollectionsMarshal.AsSpan(possible);
+        return GetRandomTrainer(span);
     }
 
-    private static ITrainerInfo? GetRandomTrainer(IReadOnlyList<KeyValuePair<GameVersion, List<ITrainerInfo>>> possible)
+    private static ITrainerInfo? GetRandomTrainer(ReadOnlySpan<KeyValuePair<GameVersion, List<ITrainerInfo>>> possible)
     {
-        if (possible.Count == 0)
+        if (possible.Length == 0)
             return null;
-        var group = GetRandomChoice(possible);
-        return GetRandomChoice(group.Value);
+        var group = possible[GetRandomIndex(possible.Length)];
+        var span = group.Value;
+        return span[GetRandomIndex(span.Count)];
     }
 
     /// <summary>
diff --git a/PKHeX.Core/Game/GameStrings/GameStrings.cs b/PKHeX.Core/Game/GameStrings/GameStrings.cs
index 8c45f8a0a..f8198752d 100644
--- a/PKHeX.Core/Game/GameStrings/GameStrings.cs
+++ b/PKHeX.Core/Game/GameStrings/GameStrings.cs
@@ -723,6 +723,7 @@ private string[] GetItemStrings9()
 
         static void InsertZero(Span<string> arr, string insert)
         {
+            // TM #'s are always ending with ##, so insert before the last 2 characters
             foreach (ref var str in arr)
                 str = str.Insert(str.Length - 2, insert);
         }
diff --git a/PKHeX.Core/Legality/Bulk/BulkAnalysis.cs b/PKHeX.Core/Legality/Bulk/BulkAnalysis.cs
index ac4eb0565..8d8808139 100644
--- a/PKHeX.Core/Legality/Bulk/BulkAnalysis.cs
+++ b/PKHeX.Core/Legality/Bulk/BulkAnalysis.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Runtime.InteropServices;
 
 namespace PKHeX.Core.Bulk;
 
@@ -36,7 +37,7 @@ public BulkAnalysis(SaveFile sav, BulkAnalysisSettings settings)
         SlotInfoLoader.AddFromSaveFile(sav, list);
         list.RemoveAll(IsEmptyData);
         AllData = list;
-        AllAnalysis = GetIndividualAnalysis(list);
+        AllAnalysis = GetIndividualAnalysis(CollectionsMarshal.AsSpan(list));
         CloneFlags = new bool[AllData.Count];
 
         ScanAll();
@@ -95,12 +96,12 @@ public void AddLine(SlotCache first, string msg, CheckIdentifier i, Severity s =
         Parse.Add(chk);
     }
 
-    private static LegalityAnalysis[] GetIndividualAnalysis(IReadOnlyList<SlotCache> pkms)
+    private static LegalityAnalysis[] GetIndividualAnalysis(ReadOnlySpan<SlotCache> list)
     {
-        var results = new LegalityAnalysis[pkms.Count];
-        for (int i = 0; i < pkms.Count; i++)
-            results[i] = Get(pkms[i]);
-        return results;
+        var result = new LegalityAnalysis[list.Length];
+        for (int i = 0; i < list.Length; i++)
+            result[i] = Get(list[i]);
+        return result;
     }
 
     private static LegalityAnalysis Get(SlotCache cache) => new(cache.Entity, cache.SAV.Personal, cache.Source.Type);
diff --git a/PKHeX.Core/Legality/Encounters/Data/Gen1/Encounters1GBEra.cs b/PKHeX.Core/Legality/Encounters/Data/Gen1/Encounters1GBEra.cs
index af35893bf..2b3c4a3db 100644
--- a/PKHeX.Core/Legality/Encounters/Data/Gen1/Encounters1GBEra.cs
+++ b/PKHeX.Core/Legality/Encounters/Data/Gen1/Encounters1GBEra.cs
@@ -8,13 +8,13 @@ internal static class Encounters1GBEra
 
     private static EncounterGift1[] GetGifts(ReadOnlySpan<byte> bin)
     {
-        const int Size = EncounterGift1.SerializedSize;
-        var result = new EncounterGift1[bin.Length / Size];
+        const int size = EncounterGift1.SerializedSize;
+        var result = new EncounterGift1[bin.Length / size];
         for (int i = 0; i < result.Length; i++)
         {
-            var data = bin[..Size];
+            var data = bin[..size];
             result[i] = new EncounterGift1(data);
-            bin = bin[Size..];
+            bin = bin[size..];
         }
         return result;
     }
diff --git a/PKHeX.Core/Legality/Encounters/Data/Gen2/Encounters2GBEra.cs b/PKHeX.Core/Legality/Encounters/Data/Gen2/Encounters2GBEra.cs
index f0a483869..08e40cc1a 100644
--- a/PKHeX.Core/Legality/Encounters/Data/Gen2/Encounters2GBEra.cs
+++ b/PKHeX.Core/Legality/Encounters/Data/Gen2/Encounters2GBEra.cs
@@ -8,13 +8,13 @@ internal static class Encounters2GBEra
 
     private static EncounterGift2[] GetGifts(ReadOnlySpan<byte> bin)
     {
-        const int Size = EncounterGift2.SerializedSize;
-        var result = new EncounterGift2[bin.Length / Size];
+        const int size = EncounterGift2.SerializedSize;
+        var result = new EncounterGift2[bin.Length / size];
         for (int i = 0; i < result.Length; i++)
         {
-            var data = bin[..Size];
+            var data = bin[..size];
             result[i] = new EncounterGift2(data);
-            bin = bin[Size..];
+            bin = bin[size..];
         }
         return result;
     }
diff --git a/PKHeX.Core/Legality/Encounters/Data/Gen3/EncountersWC3.cs b/PKHeX.Core/Legality/Encounters/Data/Gen3/EncountersWC3.cs
index c7799ad19..cfe18554a 100644
--- a/PKHeX.Core/Legality/Encounters/Data/Gen3/EncountersWC3.cs
+++ b/PKHeX.Core/Legality/Encounters/Data/Gen3/EncountersWC3.cs
@@ -10,7 +10,7 @@ namespace PKHeX.Core;
 /// Generation 3 <see cref="EncounterGift3"/> Gifts
 /// </summary>
 /// <remarks>
-/// Generation 3 has a wide range of PIDIV types and other restrictions, and was never consistently stored in raw bytes.
+/// Generation 3 has a wide range of PID/IV types and other restrictions, and was never consistently stored in raw bytes.
 /// Normally we'd just load the data from a binary, but without raw data... hard-code everything by hand.
 /// </remarks>
 internal static class EncountersWC3
diff --git a/PKHeX.Core/Legality/Encounters/Generator/EncounterFinder.cs b/PKHeX.Core/Legality/Encounters/Generator/EncounterFinder.cs
index b5a577dbc..a148074c6 100644
--- a/PKHeX.Core/Legality/Encounters/Generator/EncounterFinder.cs
+++ b/PKHeX.Core/Legality/Encounters/Generator/EncounterFinder.cs
@@ -72,7 +72,7 @@ public static void FindVerifiedEncounter(PKM pk, LegalInfo info)
         {
             if (!info.FrameMatches) // if false, all valid RNG frame matches have already been consumed
                 info.Parse.Add(new CheckResult(ParseSettings.Settings.FramePattern.GetSeverity(info.Generation), CheckIdentifier.PID, LEncConditionBadRNGFrame));
-            else if (!info.PIDIVMatches) // if false, all valid PIDIV matches have already been consumed
+            else if (!info.PIDIVMatches) // if false, all valid PID/IV matches have already been consumed
                 info.Parse.Add(new CheckResult(Severity.Invalid, CheckIdentifier.PID, LPIDTypeMismatch));
         }
     }
diff --git a/PKHeX.Core/Legality/Encounters/Templates/GO/EncounterSlot8GO.cs b/PKHeX.Core/Legality/Encounters/Templates/GO/EncounterSlot8GO.cs
index 1946240cd..f7e07e95f 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/GO/EncounterSlot8GO.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/GO/EncounterSlot8GO.cs
@@ -300,7 +300,7 @@ public bool IsWithinDistributionWindow(DateOnly date)
         return this.IsWithinStartEnd(stamp);
     }
 
-    private bool IsFormArgIncorrect(ISpeciesForm pk) => Species switch
+    private bool IsFormArgIncorrect<T>(T pk) where T : ISpeciesForm => Species switch
     {
         // Evolved without Form Argument changing from default
         (int)Yamask     when pk.Species != Species && Form == 1 => pk is IFormArgument { FormArgument: 0 },
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen1/EncounterTrade1.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen1/EncounterTrade1.cs
index e0ae46418..8bd3bc7ad 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen1/EncounterTrade1.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen1/EncounterTrade1.cs
@@ -23,7 +23,7 @@ public sealed record EncounterTrade1 : IEncounterable, IEncounterMatch, IFixedTr
     public bool IsFixedTrainer => true;
     public bool IsFixedNickname => true;
 
-    private string[] Nicknames { get; }
+    private readonly ReadOnlyMemory<string> Nicknames;
     public ushort Species { get; }
     public byte Form => 0;
     public bool EvolveOnTrade { get; init; }
@@ -61,7 +61,7 @@ private bool IsNicknameValid(PKM pk, ReadOnlySpan<char> nick)
             // Special consideration for Hiragana strings that are transferred
             if (Version == GameVersion.YW && Species == (int)Core.Species.Dugtrio)
                 return nick is "ぐりお";
-            return nick.SequenceEqual(Nicknames[1]);
+            return nick.SequenceEqual(Nicknames.Span[(int)LanguageID.Japanese]);
         }
 
         return GetNicknameIndex(nick) >= 2;
@@ -83,7 +83,7 @@ private static bool IsTrainerNameValid(PKM pk)
         return trainer.SequenceEqual(expect);
     }
 
-    private int GetNicknameIndex(ReadOnlySpan<char> nickname) => GetIndex(nickname, Nicknames);
+    private int GetNicknameIndex(ReadOnlySpan<char> nickname) => GetIndex(nickname, Nicknames.Span);
 
     private static int GetIndex(ReadOnlySpan<char> name, ReadOnlySpan<string> arr)
     {
@@ -125,7 +125,7 @@ public PK1 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             CatchRate = pi.CatchRate,
             DV16 = EncounterUtil.GetRandomDVs(Util.Rand),
 
-            Nickname = Nicknames[lang],
+            Nickname = Nicknames.Span[lang],
             TID16 = tr.TID16,
             Type1 = pi.Type1,
             Type2 = pi.Type2,
@@ -145,7 +145,7 @@ public PK1 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
     #region Matching
     public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => IsTrainerNameValid(pk);
     public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => IsNicknameValid(pk, nickname);
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     public EncounterMatchRating GetMatchRating(PKM pk)
     {
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen2/EncounterGift2.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen2/EncounterGift2.cs
index 99819f4bb..e78844434 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen2/EncounterGift2.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen2/EncounterGift2.cs
@@ -256,7 +256,7 @@ private static bool IsTrainerName(PKM pk, [ConstantExpected] string name)
         return ot[..len].SequenceEqual(name);
     }
 
-    private bool IsTrainerIDValid(ITrainerID16 pk) => Trainer switch
+    private bool IsTrainerIDValid<T>(T pk) where T : ITrainerID16 => Trainer switch
     {
         Recipient => true,
         GiftStadiumJPN => pk.TID16 == TrainerIDStadiumJPN,
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen2/EncounterTrade2.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen2/EncounterTrade2.cs
index fab7a4e5b..b6f786aad 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen2/EncounterTrade2.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen2/EncounterTrade2.cs
@@ -29,8 +29,8 @@ public sealed record EncounterTrade2 : IEncounterable, IEncounterMatch, IFixedTr
     public byte LevelMin => Level;
     public byte LevelMax => 100;
 
-    private string[] TrainerNames { get; }
-    private string[] Nicknames { get; }
+    private readonly ReadOnlyMemory<string> TrainerNames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
     public byte Gender { get; init; }
     public byte OTGender { get; init; }
@@ -66,8 +66,8 @@ public PK2 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
 
             MetLocation = Location,
 
-            Nickname = Nicknames[lang],
-            OriginalTrainerName = TrainerNames[lang],
+            Nickname = Nicknames.Span[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
             OriginalTrainerFriendship = pi.BaseFriendship,
         };
 
@@ -151,17 +151,17 @@ private int DetectLanguage(PKM pk, ReadOnlySpan<char> trainer, ReadOnlySpan<char
     {
         if (pk.Japanese)
         {
-            if (!nickname.SequenceEqual(Nicknames[(int)LanguageID.Japanese]))
+            if (!nickname.SequenceEqual(Nicknames.Span[(int)LanguageID.Japanese]))
                 return -1;
-            if (!trainer.SequenceEqual(TrainerNames[(int)LanguageID.Japanese]))
+            if (!trainer.SequenceEqual(TrainerNames.Span[(int)LanguageID.Japanese]))
                 return -1;
             return (int)LanguageID.Japanese;
         }
         if (pk.Korean)
         {
-            if (!nickname.SequenceEqual(Nicknames[(int)LanguageID.Korean]))
+            if (!nickname.SequenceEqual(Nicknames.Span[(int)LanguageID.Korean]))
                 return -1;
-            if (!trainer.SequenceEqual(TrainerNames[(int)LanguageID.Korean]))
+            if (!trainer.SequenceEqual(TrainerNames.Span[(int)LanguageID.Korean]))
                 return -1;
             return (int)LanguageID.Korean;
         }
@@ -170,7 +170,7 @@ private int DetectLanguage(PKM pk, ReadOnlySpan<char> trainer, ReadOnlySpan<char
         {
             if (i == (int)LanguageID.UNUSED_6)
                 continue;
-            if (!nickname.SequenceEqual(Nicknames[i]))
+            if (!nickname.SequenceEqual(Nicknames.Span[i]))
                 continue;
             if (IsTrainerMatchExact(pk, trainer, i))
                 return i;
@@ -180,24 +180,25 @@ private int DetectLanguage(PKM pk, ReadOnlySpan<char> trainer, ReadOnlySpan<char
 
     private int DetectLanguageNickname(PKM pk, ReadOnlySpan<char> nickname)
     {
+        var names = Nicknames.Span;
         if (pk.Japanese)
         {
-            if (!nickname.SequenceEqual(Nicknames[(int)LanguageID.Japanese]))
+            if (!nickname.SequenceEqual(names[(int)LanguageID.Japanese]))
                 return -1;
             return (int)LanguageID.Japanese;
         }
         if (pk.Korean)
         {
-            if (!nickname.SequenceEqual(Nicknames[(int)LanguageID.Korean]))
+            if (!nickname.SequenceEqual(names[(int)LanguageID.Korean]))
                 return -1;
             return (int)LanguageID.Korean;
         }
 
-        for (int i = 2; i < Nicknames.Length; i++)
+        for (int i = 2; i < names.Length; i++)
         {
             if (i == (int)LanguageID.UNUSED_6)
                 continue;
-            if (nickname.SequenceEqual(Nicknames[i]))
+            if (nickname.SequenceEqual(names[i]))
                 return i;
         }
         return -1;
@@ -205,20 +206,21 @@ private int DetectLanguageNickname(PKM pk, ReadOnlySpan<char> nickname)
 
     private int DetectLanguageTrainer(PKM pk, ReadOnlySpan<char> trainer)
     {
+        var names = TrainerNames.Span;
         if (pk.Japanese)
         {
-            if (!trainer.SequenceEqual(TrainerNames[(int)LanguageID.Japanese]))
+            if (!trainer.SequenceEqual(names[(int)LanguageID.Japanese]))
                 return -1;
             return (int)LanguageID.Japanese;
         }
         if (pk.Korean)
         {
-            if (!trainer.SequenceEqual(TrainerNames[(int)LanguageID.Korean]))
+            if (!trainer.SequenceEqual(names[(int)LanguageID.Korean]))
                 return -1;
             return (int)LanguageID.Korean;
         }
 
-        for (int i = 2; i < TrainerNames.Length; i++)
+        for (int i = 2; i < names.Length; i++)
         {
             if (i == (int)LanguageID.UNUSED_6)
                 continue;
@@ -230,7 +232,7 @@ private int DetectLanguageTrainer(PKM pk, ReadOnlySpan<char> trainer)
 
     private bool IsTrainerMatchExact(PKM pk, ReadOnlySpan<char> trainer, int language)
     {
-        var expect = pk.Format < 7 ? TrainerNames[language] : GetExpectedOT(Species, language, pk.Language);
+        var expect = pk.Format < 7 ? TrainerNames.Span[language] : GetExpectedOT(Species, language, pk.Language);
         return trainer.SequenceEqual(expect);
     }
 
@@ -239,7 +241,7 @@ private bool IsTrainerMatchExact(PKM pk, ReadOnlySpan<char> trainer, int languag
         // Can't transfer verbatim with Spanish origin glyphs to French VC.
         (int)Voltorb when language == (int)LanguageID.Spanish && pkLanguage == (int)LanguageID.French => "FALCçN", // FALCÁN
         (int)Shuckle when language == (int)LanguageID.Spanish && pkLanguage == (int)LanguageID.French => "MANôA", // MANÍA
-        _ => TrainerNames[language],
+        _ => TrainerNames.Span[language],
     };
 
     // Already required for encounter matching.
@@ -275,7 +277,7 @@ public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int _)
         return lang != -1;
     }
 
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     #endregion
 }
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen3/Colo/EncounterGift3Colo.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen3/Colo/EncounterGift3Colo.cs
index 99f33f597..dd1958c16 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen3/Colo/EncounterGift3Colo.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen3/Colo/EncounterGift3Colo.cs
@@ -21,7 +21,7 @@ public sealed record EncounterGift3Colo : IEncounterable, IEncounterMatch, IEnco
     public bool IsFixedTrainer => true;
     public bool IsJapaneseBonusDisk => Version == GameVersion.R;
 
-    private readonly string[] TrainerNames;
+    private readonly ReadOnlyMemory<string> TrainerNames;
     public ushort Species { get; }
     public byte Level { get; }
     public required byte Location { get; init; }
@@ -29,7 +29,7 @@ public sealed record EncounterGift3Colo : IEncounterable, IEncounterMatch, IEnco
     public required ushort TID16 { get; init; }
     public required byte OriginalTrainerGender { get; init; }
 
-    public EncounterGift3Colo(ushort species, byte level, string[] trainers, GameVersion game)
+    public EncounterGift3Colo(ushort species, byte level, ReadOnlyMemory<string> trainers, GameVersion game)
     {
         Species = species;
         Level = level;
@@ -63,7 +63,7 @@ public CK3 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Ball = (byte)Ball.Poke,
 
             Language = lang,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
             OriginalTrainerGender = OriginalTrainerGender,
             ID32 = TID16,
             Nickname = SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
@@ -166,7 +166,7 @@ public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language)
         if ((uint)language >= TrainerNames.Length)
             return false;
 
-        var expect = TrainerNames[language].AsSpan();
+        var expect = TrainerNames.Span[language].AsSpan();
         if (pk is CK3 && expect.SequenceEqual(trainer))
             return true; // not yet transferred to mainline Gen3
 
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen3/EncounterStatic3.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen3/EncounterStatic3.cs
index a86317782..1a1341b02 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen3/EncounterStatic3.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen3/EncounterStatic3.cs
@@ -196,8 +196,8 @@ public bool IsCompatible(PIDType type, PKM pk)
 
     private static bool IsRoamerPIDIV(PIDType val, PKM pk)
     {
-        // Roamer PIDIV is always Method 1.
-        // M1 is checked before M1R. A M1R PIDIV can also be a M1 PIDIV, so check that collision.
+        // Roamer PID/IV is always Method 1.
+        // M1 is checked before M1R. A M1R PID/IV can also be a M1 PID/IV, so check that collision.
         if (PIDType.Method_1_Roamer == val)
             return true;
         if (PIDType.Method_1 != val)
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen3/EncounterTrade3.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen3/EncounterTrade3.cs
index 9728495f5..18e4636dc 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen3/EncounterTrade3.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen3/EncounterTrade3.cs
@@ -20,8 +20,8 @@ public sealed record EncounterTrade3 : IEncounterable, IEncounterMatch, IFixedTr
     public bool IsFixedNickname => true;
     public Nature Nature => (Nature)(PID % 25);
 
-    private string[] TrainerNames { get; }
-    private string[] Nicknames { get; }
+    private readonly ReadOnlyMemory<string> TrainerNames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
     public required AbilityPermission Ability { get; init; }
     public required byte Gender { get; init; }
@@ -108,8 +108,8 @@ public PK3 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
         // Italian LG Jynx untranslated from English name
         if (Species == (int)Core.Species.Jynx && version == GameVersion.LG && lang == (int)LanguageID.Italian)
             lang = 2;
-        pk.Nickname = Nicknames[lang];
-        pk.OriginalTrainerName = TrainerNames[lang];
+        pk.Nickname = Nicknames.Span[lang];
+        pk.OriginalTrainerName = TrainerNames.Span[lang];
 
         EncounterUtil.SetEncounterMoves(pk, Version, Level);
         SetPINGA(pk, criteria);
@@ -164,9 +164,11 @@ public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language)
     {
         if (Species == (int)Core.Species.Jynx && pk.Version == GameVersion.LG && language == (int)LanguageID.Italian)
             language = 2;
-        if (language == 0 || (uint)language >= TrainerNames.Length)
+
+        var names = TrainerNames.Span;
+        if (language == 0 || (uint)language >= names.Length)
             return false;
-        var name = TrainerNames[language];
+        var name = names[language];
         if (pk.Context == EntityContext.Gen3)
             return trainer.SequenceEqual(name);
 
@@ -179,9 +181,11 @@ public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language)
     {
         if (Species == (int)Core.Species.Jynx && pk.Version == GameVersion.LG && language == (int)LanguageID.Italian)
             language = 2;
-        if (language == 0 || (uint)language >= TrainerNames.Length)
+
+        var names = Nicknames.Span;
+        if (language == 0 || (uint)language >= names.Length)
             return false;
-        var name = Nicknames[language];
+        var name = names[language];
         if (pk.Context == EntityContext.Gen3)
             return nickname.SequenceEqual(name);
 
@@ -192,7 +196,7 @@ public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language)
         return nickname.SequenceEqual(tmp);
     }
 
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     #endregion
 }
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen3/XD/EncounterTrade3XD.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen3/XD/EncounterTrade3XD.cs
index c6c787cee..abb036361 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen3/XD/EncounterTrade3XD.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen3/XD/EncounterTrade3XD.cs
@@ -32,13 +32,13 @@ public sealed record EncounterTrade3XD : IEncounterable, IEncounterMatch, IEncou
     public required ushort TID16 { get; init; }
     // SID: Based on player ID
 
-    private readonly string[] TrainerNames;
+    private readonly ReadOnlyMemory<string> TrainerNames;
 
-    private readonly string[] Nicknames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
-    public EncounterTrade3XD(ushort species, byte level, string[] trainer) : this(species, level, trainer, []) { }
+    public EncounterTrade3XD(ushort species, byte level, ReadOnlyMemory<string> trainer) : this(species, level, trainer, ReadOnlyMemory<string>.Empty) { }
 
-    public EncounterTrade3XD(ushort species, byte level, string[] trainer, string[] nicknames)
+    public EncounterTrade3XD(ushort species, byte level, ReadOnlyMemory<string> trainer, ReadOnlyMemory<string> nicknames)
     {
         Species = species;
         Level = level;
@@ -72,7 +72,7 @@ public XK3 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Ball = (byte)Ball.Poke,
             FatefulEncounter = FatefulEncounter,
             Language = lang,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
             OriginalTrainerGender = 0,
             TID16 = TID16,
             SID16 = tr.SID16,
@@ -179,7 +179,7 @@ public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language)
             return false;
         if (language == 0 || (uint)language >= TrainerNames.Length)
             return false;
-        var name = TrainerNames[language];
+        var name = TrainerNames.Span[language];
         if (pk.Context == EntityContext.Gen3)
             return trainer.SequenceEqual(name);
         if (IsSpanishDuking(language)) // Gen4+
@@ -195,7 +195,7 @@ public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language)
             return true;
         if (language == 0 || (uint)language >= Nicknames.Length)
             return false;
-        var name = Nicknames[language];
+        var name = Nicknames.Span[language];
         if (pk.Context == EntityContext.Gen3)
             return nickname.SequenceEqual(name);
 
@@ -204,5 +204,5 @@ public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language)
         return nickname.SequenceEqual(tmp);
     }
 
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 }
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen4/EncounterTrade4PID.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen4/EncounterTrade4PID.cs
index 7a3fa0f0d..16f3fd0fd 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen4/EncounterTrade4PID.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen4/EncounterTrade4PID.cs
@@ -21,8 +21,8 @@ public sealed record EncounterTrade4PID
     public byte LevelMax => IsMetUnset ? Level : (byte)100;
     public ushort Location => IsMetUnset ? Locations.LinkTrade4NPC : MetLocation;
 
-    private readonly string[] TrainerNames;
-    private readonly string[] Nicknames;
+    private readonly ReadOnlyMemory<string> TrainerNames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
     public ushort Species { get; }
     public byte Level { get; }
@@ -96,12 +96,12 @@ public PK4 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Version = version,
             Language = GetReceivedLanguage(lang, version),
             OriginalTrainerGender = OTGender,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
 
             OriginalTrainerFriendship = pi.BaseFriendship,
 
             IsNicknamed = true,
-            Nickname = Nicknames[lang],
+            Nickname = Nicknames.Span[lang],
 
             HandlingTrainerName = tr.OT,
             HandlingTrainerGender = tr.Gender,
@@ -148,9 +148,9 @@ private int GetLanguageDPPt(int lang, GameVersion game)
 
     #region Matching
 
-    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames[language]);
-    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames[language]);
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames.Span[language]);
+    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames.Span[language]);
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     public bool IsMatchExact(PKM pk, EvoCriteria evo)
     {
@@ -235,7 +235,7 @@ public int DetectOriginalLanguage(PKM pk)
         var len = pk.LoadString(pk.OriginalTrainerTrash, trainer);
         trainer = trainer[..len];
 
-        var expect = TrainerNames[1];
+        var expect = TrainerNames.Span[(int)LanguageID.Japanese];
         var match = trainer.SequenceEqual(expect);
         if (!match)
             return 2; // verify strings with English locale instead.
@@ -255,7 +255,8 @@ private int DetectTradeLanguageG4MeisterMagikarp(PKM pk, int currentLanguageID)
             var len = pk.LoadString(pk.NicknameTrash, nickname);
             nickname = nickname[..len];
 
-            return nickname.SequenceEqual(Nicknames[(int)LanguageID.French]) ? (int)LanguageID.French : (int)LanguageID.Spanish; // Spanish is same as English
+            var french = Nicknames.Span[(int)LanguageID.French];
+            return nickname.SequenceEqual(french) ? (int)LanguageID.French : (int)LanguageID.Spanish; // Spanish is same as English
         }
 
         return lang;
@@ -274,7 +275,8 @@ private int DetectTradeLanguageG4SurgePikachu(PKM pk, int currentLanguageID)
             var len = pk.LoadString(pk.NicknameTrash, nickname);
             nickname = nickname[..len];
 
-            return nickname.SequenceEqual(Nicknames[(int)LanguageID.Italian]) ? (int)LanguageID.Italian : (int)LanguageID.Spanish;
+            var italian = Nicknames.Span[(int)LanguageID.Italian];
+            return nickname.SequenceEqual(italian) ? (int)LanguageID.Italian : (int)LanguageID.Spanish;
         }
 
         return lang;
@@ -282,7 +284,7 @@ private int DetectTradeLanguageG4SurgePikachu(PKM pk, int currentLanguageID)
 
     private int DetectTradeLanguage(ReadOnlySpan<char> actual, int currentLanguageID)
     {
-        var names = TrainerNames;
+        var names = TrainerNames.Span;
         for (int lang = 1; lang < names.Length; lang++)
         {
             var expect = names[lang];
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen5/EncounterTrade5B2W2.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen5/EncounterTrade5B2W2.cs
index 54c7541e5..956a0c049 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen5/EncounterTrade5B2W2.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen5/EncounterTrade5B2W2.cs
@@ -31,8 +31,8 @@ public sealed record EncounterTrade5B2W2 : IEncounterable, IEncounterMatch, IFix
     public IndividualValueSet IVs { get; init; }
     public Nature Nature { get; init; } = Nature.Random;
 
-    private readonly string[] TrainerNames;
-    private readonly string[] Nicknames;
+    private readonly ReadOnlyMemory<string> TrainerNames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
     private const string _name = "In-game Trade";
     public string Name => _name;
@@ -54,7 +54,7 @@ public EncounterTrade5B2W2(string[] names, GameVersion version)
         Version = version;
         Gender = FixedGenderUtil.GenderRandom;
         Nature = Nature.Random;
-        Nicknames = [];
+        Nicknames = ReadOnlyMemory<string>.Empty;
         TrainerNames = names;
         IsFixedNickname = false;
     }
@@ -86,12 +86,12 @@ public PK5 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Version = version,
             Language = lang,
             OriginalTrainerGender = OTGender,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
 
             OriginalTrainerFriendship = pi.BaseFriendship,
 
             IsNicknamed = IsFixedNickname,
-            Nickname = IsFixedNickname ? Nicknames[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
+            Nickname = IsFixedNickname ? Nicknames.Span[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
         };
 
         EncounterUtil.SetEncounterMoves(pk, version, Level);
@@ -116,9 +116,9 @@ private void SetPINGA(PK5 pk, EncounterCriteria criteria, PersonalInfo5B2W2 pi)
 
     #region Matching
 
-    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames[language]);
-    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames[language]);
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames.Span[language]);
+    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames.Span[language]);
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     public bool IsMatchExact(PKM pk, EvoCriteria evo)
     {
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen5/EncounterTrade5BW.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen5/EncounterTrade5BW.cs
index 76b67516c..2ca9e9497 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen5/EncounterTrade5BW.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen5/EncounterTrade5BW.cs
@@ -19,8 +19,8 @@ public sealed record EncounterTrade5BW : IEncounterable, IEncounterMatch, IFixed
     public byte LevelMin => Level;
     public byte LevelMax => Level;
 
-    private string[] TrainerNames { get; }
-    private string[] Nicknames { get; }
+    private readonly ReadOnlyMemory<string> TrainerNames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
     public required ushort Species { get; init; }
     public required byte Level { get; init; }
@@ -86,12 +86,12 @@ public PK5 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Version = version,
             Language = lang == 1 ? 0 : lang, // Trades for JPN games have language ID of 0, not 1.
             OriginalTrainerGender = OTGender,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
 
             OriginalTrainerFriendship = pi.BaseFriendship,
 
             IsNicknamed = IsFixedNickname,
-            Nickname = IsFixedNickname ? Nicknames[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
+            Nickname = IsFixedNickname ? Nicknames.Span[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
         };
 
         EncounterUtil.SetEncounterMoves(pk, version, Level);
@@ -106,9 +106,9 @@ public PK5 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
 
     #region Matching
 
-    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames[language]);
-    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames[language]);
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames.Span[language]);
+    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames.Span[language]);
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     public bool IsMatchExact(PKM pk, EvoCriteria evo)
     {
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen6/EncounterTrade6.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen6/EncounterTrade6.cs
index c797f0ae8..9039bc14d 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen6/EncounterTrade6.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen6/EncounterTrade6.cs
@@ -18,8 +18,8 @@ public sealed record EncounterTrade6 : IEncounterable, IEncounterMatch, IFixedTr
     public bool IsFixedTrainer => true;
     public bool IsFixedNickname { get; init; } = true;
 
-    private string[] TrainerNames { get; }
-    private string[] Nicknames { get; }
+    private readonly ReadOnlyMemory<string> TrainerNames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
     public required Nature Nature { get; init; }
     public required ushort ID32 { get; init; }
@@ -84,7 +84,7 @@ public PK6 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Version = version,
             Language = lang,
             OriginalTrainerGender = OTGender,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
 
             OriginalTrainerMemory = OriginalTrainerMemory,
             OriginalTrainerMemoryIntensity = OriginalTrainerMemoryIntensity,
@@ -93,7 +93,7 @@ public PK6 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             OriginalTrainerFriendship = pi.BaseFriendship,
 
             IsNicknamed = IsFixedNickname,
-            Nickname = IsFixedNickname ? Nicknames[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
+            Nickname = IsFixedNickname ? Nicknames.Span[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
 
             HandlingTrainerName = tr.OT,
             HandlingTrainerGender = tr.Gender,
@@ -119,14 +119,14 @@ public PK6 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
 
     #region Matching
 
-    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames[language]);
+    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames.Span[language]);
     public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language)
     {
         if (Species is (ushort)Core.Species.Farfetchd && nickname is "Quacklin’" or "Quacklin'")
             return true;
-        return (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames[language]);
+        return (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames.Span[language]);
     }
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     public bool IsMatchExact(PKM pk, EvoCriteria evo)
     {
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen7/EncounterTrade7.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen7/EncounterTrade7.cs
index 67a5ffda1..9a84c19af 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen7/EncounterTrade7.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen7/EncounterTrade7.cs
@@ -22,8 +22,8 @@ public sealed record EncounterTrade7 : IEncounterable, IEncounterMatch, IFixedTr
     public bool IsFixedTrainer => true;
     public bool IsFixedNickname => true;
 
-    private string[] TrainerNames { get; }
-    private string[] Nicknames { get; }
+    private readonly ReadOnlyMemory<string> TrainerNames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
     public required Nature Nature { get; init; }
     public required uint ID32 { get; init; }
@@ -83,7 +83,7 @@ public PK7 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Version = version,
             Language = lang,
             OriginalTrainerGender = OTGender,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
 
             OriginalTrainerMemory = OriginalTrainerMemory,
             OriginalTrainerMemoryIntensity = OriginalTrainerMemoryIntensity,
@@ -92,7 +92,7 @@ public PK7 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             OriginalTrainerFriendship = pi.BaseFriendship,
 
             IsNicknamed = true,
-            Nickname = Nicknames[lang],
+            Nickname = Nicknames.Span[lang],
 
             HandlingTrainerName = tr.OT,
             HandlingTrainerGender = tr.Gender,
@@ -121,9 +121,9 @@ public PK7 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
 
     #region Matching
 
-    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames[language]);
-    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames[language]);
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames.Span[language]);
+    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames.Span[language]);
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     public bool IsMatchExact(PKM pk, EvoCriteria evo)
     {
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen7b/EncounterTrade7b.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen7b/EncounterTrade7b.cs
index 2d5284879..001ee0694 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen7b/EncounterTrade7b.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen7b/EncounterTrade7b.cs
@@ -18,7 +18,7 @@ public sealed record EncounterTrade7b(GameVersion Version) : IEncounterable, IEn
     public bool IsFixedTrainer => true;
     public AbilityPermission Ability => AbilityPermission.Any12;
 
-    public required string[] TrainerNames { get; init; }
+    public required ReadOnlyMemory<string> TrainerNames { get; init; }
 
     public required uint ID32 { get; init; }
     public required byte OTGender { get; init; }
@@ -60,7 +60,7 @@ public PB7 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Version = version,
             Language = lang,
             OriginalTrainerGender = OTGender,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
 
             OriginalTrainerFriendship = pi.BaseFriendship,
 
@@ -100,7 +100,7 @@ private void SetPINGA(PB7 pk, EncounterCriteria criteria, PersonalInfo7GG pi)
 
     #region Matching
 
-    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames[language]);
+    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames.Span[language]);
 
     public bool IsMatchExact(PKM pk, EvoCriteria evo)
     {
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen8/EncounterStatic8U.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen8/EncounterStatic8U.cs
index e6e3e41be..d56c5c56e 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen8/EncounterStatic8U.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen8/EncounterStatic8U.cs
@@ -70,6 +70,6 @@ protected override void SetTrainerName(ReadOnlySpan<char> name, PK8 pk)
         (int)LanguageID.Korean => "연구원",
         (int)LanguageID.ChineseS => "研究员",
         (int)LanguageID.ChineseT => "研究員",
-        _ => ReadOnlySpan<char>.Empty,
+        _ => [],
     };
 }
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen8/EncounterTrade8.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen8/EncounterTrade8.cs
index c2c83dbdf..4cd96e0ce 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen8/EncounterTrade8.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen8/EncounterTrade8.cs
@@ -28,8 +28,8 @@ public sealed record EncounterTrade8 : IEncounterable, IEncounterMatch, IFixedTr
     public bool IsFixedTrainer => true;
     public bool IsFixedNickname { get; }
 
-    private string[] TrainerNames { get; }
-    private string[] Nicknames { get; }
+    private readonly ReadOnlyMemory<string> TrainerNames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
     public Nature Nature { get; init; } // always set by either constructor or initializer
     public required uint ID32 { get; init; }
@@ -68,10 +68,10 @@ public EncounterTrade8(ReadOnlySpan<string[]> names, byte index, GameVersion gam
     }
 
     [SetsRequiredMembers]
-    public EncounterTrade8(string[] trainerNames, GameVersion game, ushort species, byte level, byte memory, ushort arg, byte feel, byte intensity)
+    public EncounterTrade8(ReadOnlyMemory<string> trainerNames, GameVersion game, ushort species, byte level, byte memory, ushort arg, byte feel, byte intensity)
     {
         Version = game;
-        Nicknames = [];
+        Nicknames = ReadOnlyMemory<string>.Empty;
         TrainerNames = trainerNames;
         Species = species;
         Level = level;
@@ -116,7 +116,7 @@ public PK8 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Version = version,
             Language = lang,
             OriginalTrainerGender = OTGender,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
 
             OriginalTrainerMemory = OriginalTrainerMemory,
             OriginalTrainerMemoryIntensity = OriginalTrainerMemoryIntensity,
@@ -125,7 +125,7 @@ public PK8 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             OriginalTrainerFriendship = pi.BaseFriendship,
 
             IsNicknamed = IsFixedNickname,
-            Nickname = IsFixedNickname ? Nicknames[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
+            Nickname = IsFixedNickname ? Nicknames.Span[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
             DynamaxLevel = DynamaxLevel,
             HandlingTrainerName = tr.OT,
             HandlingTrainerGender = tr.Gender,
@@ -163,9 +163,9 @@ private void SetPINGA(PK8 pk, EncounterCriteria criteria, PersonalInfo8SWSH pi)
 
     #region Matching
 
-    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames[language]);
-    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames[language]);
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames.Span[language]);
+    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames.Span[language]);
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     public bool IsMatchExact(PKM pk, EvoCriteria evo)
     {
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen8b/EncounterTrade8b.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen8b/EncounterTrade8b.cs
index d74cdd938..4c34e42df 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen8b/EncounterTrade8b.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen8b/EncounterTrade8b.cs
@@ -19,8 +19,8 @@ public sealed record EncounterTrade8b : IEncounterable, IEncounterMatch, IFixedT
     public bool IsFixedNickname => true;
     public GameVersion Version { get; }
 
-    private string[] TrainerNames { get; }
-    private string[] Nicknames { get; }
+    private readonly ReadOnlyMemory<string> TrainerNames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
     public required Nature Nature { get; init; }
     public required ushort ID32 { get; init; }
@@ -91,12 +91,12 @@ public PB8 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Version = version,
             Language = lang,
             OriginalTrainerGender = OTGender,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
 
             OriginalTrainerFriendship = OriginalTrainerFriendship,
 
             IsNicknamed = IsFixedNickname,
-            Nickname = IsFixedNickname ? Nicknames[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
+            Nickname = IsFixedNickname ? Nicknames.Span[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
             HeightScalar = HeightScalar,
             WeightScalar = WeightScalar,
             HandlingTrainerName = tr.OT,
@@ -121,9 +121,9 @@ public PB8 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
 
     #region Matching
 
-    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames[language]);
-    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames[language]);
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames.Span[language]);
+    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames.Span[language]);
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     public EncounterMatchRating GetMatchRating(PKM pk) => EncounterMatchRating.Match;
 
@@ -202,11 +202,13 @@ public int DetectMeisterMagikarpLanguage(ReadOnlySpan<char> nick, ReadOnlySpan<c
         if (currentLanguageID is not ((int)LanguageID.Japanese or (int)LanguageID.German))
             return -1;
 
+        var nicknames = Nicknames.Span;
+        var trainers = TrainerNames.Span;
         for (int i = 1; i < (int)LanguageID.ChineseT; i++)
         {
-            if (!nick.SequenceEqual(Nicknames[i]))
+            if (!nick.SequenceEqual(nicknames[i]))
                 continue;
-            if (!ot.SequenceEqual(TrainerNames[i]))
+            if (!ot.SequenceEqual(trainers[i]))
                 continue;
 
             // Language gets flipped to another language ID; can't be equal.
diff --git a/PKHeX.Core/Legality/Encounters/Templates/Gen9/EncounterTrade9.cs b/PKHeX.Core/Legality/Encounters/Templates/Gen9/EncounterTrade9.cs
index e1f98d83e..2ea38e6aa 100644
--- a/PKHeX.Core/Legality/Encounters/Templates/Gen9/EncounterTrade9.cs
+++ b/PKHeX.Core/Legality/Encounters/Templates/Gen9/EncounterTrade9.cs
@@ -20,8 +20,8 @@ public sealed record EncounterTrade9
     public bool IsFixedNickname => Nicknames.Length != 0;
     public GameVersion Version { get; }
 
-    private string[] TrainerNames { get; }
-    private string[] Nicknames { get; }
+    private readonly ReadOnlyMemory<string> TrainerNames;
+    private readonly ReadOnlyMemory<string> Nicknames;
 
     public required Nature Nature { get; init; }
     public required uint ID32 { get; init; }
@@ -89,12 +89,12 @@ public PK9 ConvertToPKM(ITrainerInfo tr, EncounterCriteria criteria)
             Version = version,
             Language = lang,
             OriginalTrainerGender = OTGender,
-            OriginalTrainerName = TrainerNames[lang],
+            OriginalTrainerName = TrainerNames.Span[lang],
 
             OriginalTrainerFriendship = pi.BaseFriendship,
 
             IsNicknamed = IsFixedNickname,
-            Nickname = IsFixedNickname ? Nicknames[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
+            Nickname = IsFixedNickname ? Nicknames.Span[lang] : SpeciesName.GetSpeciesNameGeneration(Species, lang, Generation),
 
             HeightScalar = PokeSizeUtil.GetRandomScalar(rnd),
             WeightScalar = Weight.GetSizeValue(Weight != SizeType9.RANDOM ? FixedValueScale : default, ref xoro),
@@ -147,9 +147,9 @@ private MoveType GetOriginalTeraType()
 
     #region Matching
 
-    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames[language]);
-    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames[language]);
-    public string GetNickname(int language) => (uint)language < Nicknames.Length ? Nicknames[language] : Nicknames[0];
+    public bool IsTrainerMatch(PKM pk, ReadOnlySpan<char> trainer, int language) => (uint)language < TrainerNames.Length && trainer.SequenceEqual(TrainerNames.Span[language]);
+    public bool IsNicknameMatch(PKM pk, ReadOnlySpan<char> nickname, int language) => (uint)language < Nicknames.Length && nickname.SequenceEqual(Nicknames.Span[language]);
+    public string GetNickname(int language) => Nicknames.Span[(uint)language < Nicknames.Length ? language : 0];
 
     private bool IsMatchNatureGenderShiny(PKM pk)
     {
diff --git a/PKHeX.Core/Legality/Formatting/LegalityFormatting.cs b/PKHeX.Core/Legality/Formatting/LegalityFormatting.cs
index 3bc7676f4..e743e3744 100644
--- a/PKHeX.Core/Legality/Formatting/LegalityFormatting.cs
+++ b/PKHeX.Core/Legality/Formatting/LegalityFormatting.cs
@@ -88,7 +88,7 @@ public static void AddEncounterInfo(LegalityAnalysis la, List<string> lines)
         if (enc.Generation <= 2)
             lines.Add(string.Format(L_F0_1, nameof(GameVersion), enc.Version));
 
-        // PIDIV
+        // PID/IV
         AddEncounterInfoPIDIV(la, lines);
     }
 
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource4HGSS.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource4HGSS.cs
index 01681c684..d0c93d8ef 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource4HGSS.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource4HGSS.cs
@@ -77,7 +77,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo4 pi, EvoCriteria evo, usho
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species is (int)Species.Rotom && move switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species is (int)Species.Rotom && move switch
     {
         (int)Move.Overheat  => option.IsPast() || current.Form == 1,
         (int)Move.HydroPump => option.IsPast() || current.Form == 2,
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource4Pt.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource4Pt.cs
index 522ef90d9..60c633616 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource4Pt.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource4Pt.cs
@@ -75,7 +75,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo4 pi, EvoCriteria evo, usho
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species is (int)Species.Rotom && move switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species is (int)Species.Rotom && move switch
     {
         (int)Move.Overheat  => option.IsPast() || current.Form == 1,
         (int)Move.HydroPump => option.IsPast() || current.Form == 2,
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource5B2W2.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource5B2W2.cs
index e981e4efb..4812dcff8 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource5B2W2.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource5B2W2.cs
@@ -69,7 +69,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo5B2W2 pi, EvoCriteria evo,
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species switch
     {
         (int)Species.Keldeo => move is (int)Move.SecretSword,
         (int)Species.Meloetta => move is (int)Move.RelicSong,
@@ -101,7 +104,7 @@ private static bool GetIsTM(PersonalInfo5B2W2 info, ushort move)
         return info.GetIsLearnTM(index);
     }
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource5BW.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource5BW.cs
index e57b85d95..e20b125dd 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource5BW.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource5BW.cs
@@ -66,7 +66,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo5BW pi, EvoCriteria evo, us
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species switch
     {
         (int)Species.Keldeo => move is (int)Move.SecretSword,
         (int)Species.Meloetta => move is (int)Move.RelicSong,
@@ -98,7 +101,7 @@ private static bool GetIsTM(PersonalInfo5BW info, ushort move)
         return info.GetIsLearnTM(index) && index != 94; // TM95 not available in this game
     }
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource6AO.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource6AO.cs
index f040f6606..542263858 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource6AO.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource6AO.cs
@@ -70,7 +70,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo6AO pi, EvoCriteria evo, us
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species switch
     {
         (int)Species.Keldeo => move is (int)Move.SecretSword,
         (int)Species.Meloetta => move is (int)Move.RelicSong,
@@ -92,7 +95,7 @@ private static bool GetIsTM(PersonalInfo6AO info, ushort move)
         return info.GetIsLearnTM(index);
     }
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource6XY.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource6XY.cs
index 5b6f31ae7..019caddbf 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource6XY.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource6XY.cs
@@ -67,7 +67,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo6XY pi, EvoCriteria evo, us
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species switch
     {
         (int)Species.Keldeo => move is (int)Move.SecretSword,
         (int)Species.Meloetta => move is (int)Move.RelicSong,
@@ -83,7 +86,7 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo6XY pi, EvoCriteria evo, us
         _ => false,
     };
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7GG.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7GG.cs
index 60f0542a6..53fc344fd 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7GG.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7GG.cs
@@ -58,7 +58,7 @@ private static bool GetIsEnhancedTutor(ushort species, byte form, ushort move)
         return false;
     }
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7SM.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7SM.cs
index d942dfdc2..a3cc0a7c2 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7SM.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7SM.cs
@@ -69,7 +69,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo7 pi, EvoCriteria evo, usho
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species switch
     {
         (int)Species.Pikachu or (int)Species.Raichu => move is (int)Move.VoltTackle,
         (int)Species.Necrozma => move switch
@@ -93,7 +96,7 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo7 pi, EvoCriteria evo, usho
         _ => false,
     };
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
@@ -132,9 +135,9 @@ public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceTy
                 result[(int)Move.SecretSword] = true;
             else if (species is (int)Species.Meloetta)
                 result[(int)Move.RelicSong] = true;
-            else if (species is (int)Species.Necrozma && pk.Form is 1) // Sun
+            else if (species is (int)Species.Necrozma && evo.Form is 1) // Sun
                 result[(int)Move.SunsteelStrike] = true;
-            else if (species is (int)Species.Necrozma && pk.Form is 2) // Moon
+            else if (species is (int)Species.Necrozma && evo.Form is 2) // Moon
                 result[(int)Move.MoongeistBeam] = true;
         }
     }
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7USUM.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7USUM.cs
index 9af6537a4..aba5cefad 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7USUM.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource7USUM.cs
@@ -72,7 +72,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo7 pi, EvoCriteria evo, usho
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species switch
     {
         (int)Species.Pikachu or (int)Species.Raichu => move is (int)Move.VoltTackle,
         (int)Species.Necrozma => move switch
@@ -96,7 +99,7 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo7 pi, EvoCriteria evo, usho
         _ => false,
     };
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
@@ -139,9 +142,9 @@ public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceTy
                 result[(int)Move.SecretSword] = true;
             else if (species is (int)Species.Meloetta)
                 result[(int)Move.RelicSong] = true;
-            else if (species is (int)Species.Necrozma && pk.Form is 1) // Sun
+            else if (species is (int)Species.Necrozma && evo.Form is 1) // Sun
                 result[(int)Move.SunsteelStrike] = true;
-            else if (species is (int)Species.Necrozma && pk.Form is 2) // Moon
+            else if (species is (int)Species.Necrozma && evo.Form is 2) // Moon
                 result[(int)Move.MoongeistBeam] = true;
         }
     }
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8BDSP.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8BDSP.cs
index efbaa81f2..c5b6db643 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8BDSP.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8BDSP.cs
@@ -72,7 +72,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo8BDSP pi, EvoCriteria evo,
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species is (int)Species.Rotom && move switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species is (int)Species.Rotom && move switch
     {
         (int)Move.Overheat  => option.IsPast() || current.Form == 1,
         (int)Move.HydroPump => option.IsPast() || current.Form == 2,
@@ -89,7 +92,7 @@ private bool GetIsSharedEggMove(PersonalInfo8BDSP pi, ushort move)
         return GetEggMoves(baseSpecies, baseForm).Contains(move);
     }
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8PLA.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8PLA.cs
index 7f626ca9b..0d473db49 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8PLA.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8PLA.cs
@@ -56,7 +56,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo8LA pi, EvoCriteria evo, us
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species is (int)Species.Rotom && move switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species is (int)Species.Rotom && move switch
     {
         (int)Move.Overheat  => option.IsPast() || current.Form == 1,
         (int)Move.HydroPump => option.IsPast() || current.Form == 2,
@@ -66,7 +69,7 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo8LA pi, EvoCriteria evo, us
         _ => false,
     };
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8SWSH.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8SWSH.cs
index dc20b852d..086731f61 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8SWSH.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource8SWSH.cs
@@ -74,7 +74,10 @@ public MoveLearnInfo GetCanLearn(PKM pk, PersonalInfo8SWSH pi, EvoCriteria evo,
         return default;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species switch
     {
         (int)Species.Necrozma => move switch
         {
@@ -128,7 +131,7 @@ private static bool GetIsTR(PersonalInfo8SWSH info, PKM pk, EvoCriteria evo, ush
         return false;
     }
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
@@ -167,11 +170,11 @@ public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceTy
         if (types.HasFlag(MoveSourceType.EnhancedTutor))
         {
             var species = evo.Species;
-            if (species is (int)Species.Rotom && pk.Form is not 0)
+            if (species is (int)Species.Rotom && evo.Form is not 0)
                 result[MoveTutor.GetRotomFormMove(evo.Form)] = true;
-            else if (species is (int)Species.Necrozma && pk.Form is 1) // Sun
+            else if (species is (int)Species.Necrozma && evo.Form is 1) // Sun
                 result[(int)Move.SunsteelStrike] = true;
-            else if (species is (int)Species.Necrozma && pk.Form is 2) // Moon
+            else if (species is (int)Species.Necrozma && evo.Form is 2) // Moon
                 result[(int)Move.MoongeistBeam] = true;
         }
     }
diff --git a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource9SV.cs b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource9SV.cs
index 45d461f60..1303656ab 100644
--- a/PKHeX.Core/Legality/LearnSource/Sources/LearnSource9SV.cs
+++ b/PKHeX.Core/Legality/LearnSource/Sources/LearnSource9SV.cs
@@ -122,7 +122,10 @@ private static bool GetIsTM(PersonalInfo9SV info, PKM pk, ushort move, LearnOpti
         return false;
     }
 
-    private static bool GetIsEnhancedTutor(EvoCriteria evo, ISpeciesForm current, ushort move, LearnOption option) => evo.Species switch
+    private static bool GetIsEnhancedTutor<T1, T2>(T1 evo, T2 current, ushort move, LearnOption option)
+        where T1 : ISpeciesForm
+        where T2 : ISpeciesForm
+        => evo.Species switch
     {
         (int)Species.Necrozma => move switch
         {
@@ -149,7 +152,7 @@ private bool GetIsSharedEggMove(PersonalInfo9SV pi, ushort move)
         return GetEggMoves(baseSpecies, baseForm).Contains(move);
     }
 
-    public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
+    public void GetAllMoves(Span<bool> result, PKM _, EvoCriteria evo, MoveSourceType types = MoveSourceType.All)
     {
         if (!TryGetPersonal(evo.Species, evo.Form, out var pi))
             return;
@@ -184,11 +187,11 @@ public void GetAllMoves(Span<bool> result, PKM pk, EvoCriteria evo, MoveSourceTy
         if (types.HasFlag(MoveSourceType.EnhancedTutor))
         {
             var species = evo.Species;
-            if (species is (int)Species.Rotom && pk.Form is not 0)
+            if (species is (int)Species.Rotom && evo.Form is not 0)
                 result[MoveTutor.GetRotomFormMove(evo.Form)] = true;
-            else if (species is (int)Species.Necrozma && pk.Form is 1) // Sun
+            else if (species is (int)Species.Necrozma && evo.Form is 1) // Sun
                 result[(int)Move.SunsteelStrike] = true;
-            else if (species is (int)Species.Necrozma && pk.Form is 2) // Moon
+            else if (species is (int)Species.Necrozma && evo.Form is 2) // Moon
                 result[(int)Move.MoongeistBeam] = true;
         }
     }
diff --git a/PKHeX.Core/Legality/RNG/MethodFinder.cs b/PKHeX.Core/Legality/RNG/MethodFinder.cs
index abec8248d..cf6cbcd6c 100644
--- a/PKHeX.Core/Legality/RNG/MethodFinder.cs
+++ b/PKHeX.Core/Legality/RNG/MethodFinder.cs
@@ -6,12 +6,12 @@
 namespace PKHeX.Core;
 
 /// <summary>
-/// Class containing logic to obtain a PKM's PIDIV method.
+/// Class containing logic to obtain a PKM's PID/IV method.
 /// </summary>
 public static class MethodFinder
 {
     /// <summary>
-    /// Analyzes a <see cref="PKM"/> to find a matching PIDIV method.
+    /// Analyzes a <see cref="PKM"/> to find a matching PID/IV method.
     /// </summary>
     /// <param name="pk">Input <see cref="PKM"/>.</param>
     /// <returns><see cref="PIDIV"/> object containing seed and method info.</returns>
diff --git a/PKHeX.Core/Legality/RNG/Methods/Gen8b/Roaming8bRNG.cs b/PKHeX.Core/Legality/RNG/Methods/Gen8b/Roaming8bRNG.cs
index ae6ef0064..d8866315c 100644
--- a/PKHeX.Core/Legality/RNG/Methods/Gen8b/Roaming8bRNG.cs
+++ b/PKHeX.Core/Legality/RNG/Methods/Gen8b/Roaming8bRNG.cs
@@ -239,7 +239,7 @@ private static bool GetIsHeightWeightMatch(PKM pk, Xoroshiro128Plus8b xoro)
         return s.HeightScalar == height && s.WeightScalar == weight;
     }
 
-    private static uint GetRevisedPID(uint fakeTID, uint pid, ITrainerID32 tr)
+    private static uint GetRevisedPID<T>(uint fakeTID, uint pid, T tr) where T : ITrainerID32
     {
         var xor = GetShinyXor(pid, fakeTID);
         var newXor = GetShinyXor(pid, tr.ID32);
diff --git a/PKHeX.Core/Legality/RNG/Methods/Gen8b/Wild8bRNG.cs b/PKHeX.Core/Legality/RNG/Methods/Gen8b/Wild8bRNG.cs
index 37986e1c2..511d3030d 100644
--- a/PKHeX.Core/Legality/RNG/Methods/Gen8b/Wild8bRNG.cs
+++ b/PKHeX.Core/Legality/RNG/Methods/Gen8b/Wild8bRNG.cs
@@ -142,7 +142,7 @@ public static bool TryApplyFromSeed(PKM pk, EncounterCriteria criteria, Shiny sh
         return true;
     }
 
-    private static uint GetRevisedPID(uint fakeTID, uint pid, ITrainerID32 tr)
+    private static uint GetRevisedPID<T>(uint fakeTID, uint pid, T tr) where T : ITrainerID32
     {
         var xor = GetShinyXor(pid, fakeTID);
         var newXor = GetShinyXor(pid, tr.ID32);
diff --git a/PKHeX.Core/Legality/RNG/Methods/Gen9/Tera9RNG.cs b/PKHeX.Core/Legality/RNG/Methods/Gen9/Tera9RNG.cs
index 8236831f0..01f0c492b 100644
--- a/PKHeX.Core/Legality/RNG/Methods/Gen9/Tera9RNG.cs
+++ b/PKHeX.Core/Legality/RNG/Methods/Gen9/Tera9RNG.cs
@@ -70,22 +70,19 @@ public static byte GetTeraType(in ulong seed, GemType gem, in ushort species, in
             return type;
 
         var rand = new Xoroshiro128Plus(seed);
-        if (gem == GemType.Default)
-        {
-            var pivot = rand.NextInt(2);
-            return GetTeraTypeFromPersonal(species, form, pivot);
-        }
         if (gem == GemType.Random)
-        {
             return (byte)rand.NextInt(TeraTypeCount);
-        }
-        throw new ArgumentOutOfRangeException(nameof(gem), gem, null);
+        if (gem != GemType.Default)
+            throw new ArgumentOutOfRangeException(nameof(gem), gem, null);
+        var pivot = rand.NextInt(2);
+        return GetTeraTypeFromPersonal(species, form, pivot);
     }
 
     /// <summary>
     /// Checks if the original Tera Type matches either of the Personal Info types.
     /// </summary>
-    private static bool IsMatchType(IPersonalType pi, in byte original) => original == pi.Type1 || original == pi.Type2;
+    private static bool IsMatchType<T>(T pi, in byte original) where T : IPersonalType
+        => original == pi.Type1 || original == pi.Type2;
 
     /// <summary>
     /// Checks if the original Tera Type matches the Personal Info type for the specified form.
@@ -102,7 +99,7 @@ public static byte GetTeraType(in ulong seed, GemType gem, in ushort species, in
             ? IsMatchTeraTypePersonalAnyForm(species, original)
             : IsMatchTeraTypePersonal(species, form, original);
 
-    /// <inheritdoc cref="IsMatchType"/>
+    /// <inheritdoc cref="IsMatchType{T}"/>
     public static bool IsMatchTeraTypePersonal(in ushort species, in byte form, in byte original) => IsMatchType(PersonalTable.SV[species, form], original);
 
     /// <summary>
diff --git a/PKHeX.Core/Legality/RNG/PIDIV.cs b/PKHeX.Core/Legality/RNG/PIDIV.cs
index 748a0365b..af748e2a4 100644
--- a/PKHeX.Core/Legality/RNG/PIDIV.cs
+++ b/PKHeX.Core/Legality/RNG/PIDIV.cs
@@ -21,7 +21,7 @@ namespace PKHeX.Core;
     /// <summary>The RNG seed which immediately generates the PID/IV (starting with PID or IVs, whichever comes first)</summary>
     [field: FieldOffset(0)] public ulong Seed64 { get; }
 
-    /// <summary>Type of PIDIV correlation</summary>
+    /// <summary>Type of PID/IV correlation</summary>
     [field: FieldOffset(8)] public PIDType Type { get; }
     [field: FieldOffset(9)] public LeadRequired Lead { get; init; }
     [field: FieldOffset(9)] public PIDType Mutated { get; init; }
diff --git a/PKHeX.Core/MysteryGifts/WA8.cs b/PKHeX.Core/MysteryGifts/WA8.cs
index 2a5bfa517..dabea5c72 100644
--- a/PKHeX.Core/MysteryGifts/WA8.cs
+++ b/PKHeX.Core/MysteryGifts/WA8.cs
@@ -560,7 +560,7 @@ private void SetPINGA(PA8 pk, EncounterCriteria criteria)
         _ => AbilityPermission.Any12H,
     };
 
-    private uint GetPID(ITrainerID32 tr, ShinyType8 type) => type switch
+    private uint GetPID<T>(T tr, ShinyType8 type) where T : ITrainerID32 => type switch
     {
         ShinyType8.Never        => GetAntishiny(tr), // Random, Never Shiny
         ShinyType8.Random       => Util.Rand32(), // Random, Any
diff --git a/PKHeX.Core/Saves/Encryption/SwishCrypto/SCBlockCompare.cs b/PKHeX.Core/Saves/Encryption/SwishCrypto/SCBlockCompare.cs
index 72103db51..0c9ded5e5 100644
--- a/PKHeX.Core/Saves/Encryption/SwishCrypto/SCBlockCompare.cs
+++ b/PKHeX.Core/Saves/Encryption/SwishCrypto/SCBlockCompare.cs
@@ -31,7 +31,7 @@ public SCBlockCompare(SCBlockAccessor s1, SCBlockAccessor s2, IEnumerable<string
         LoadChanged(s1, s2, hs1);
     }
 
-    private void LoadAddRemove(SCBlockAccessor s1, SCBlockAccessor s2, ICollection<uint> hs1, IEnumerable<uint> hs2)
+    private void LoadAddRemove(SCBlockAccessor s1, SCBlockAccessor s2, HashSet<uint> hs1, HashSet<uint> hs2)
     {
         var unique = new HashSet<uint>(hs1);
         unique.SymmetricExceptWith(hs2);
@@ -51,7 +51,7 @@ private void LoadAddRemove(SCBlockAccessor s1, SCBlockAccessor s2, ICollection<u
         }
     }
 
-    private void LoadChanged(SCBlockAccessor s1, SCBlockAccessor s2, IEnumerable<uint> shared)
+    private void LoadChanged(SCBlockAccessor s1, SCBlockAccessor s2, IReadOnlySet<uint> shared)
     {
         foreach (var k in shared)
         {
diff --git a/PKHeX.Core/Saves/Substructures/Gen4/Geonet4.cs b/PKHeX.Core/Saves/Substructures/Gen4/Geonet4.cs
index 1d411d19f..4245fb927 100644
--- a/PKHeX.Core/Saves/Substructures/Gen4/Geonet4.cs
+++ b/PKHeX.Core/Saves/Substructures/Gen4/Geonet4.cs
@@ -67,7 +67,7 @@ public GeonetPoint GetCountrySubregion(byte country, byte subregion)
     {
         int index = ((country - 1) * 16) + (subregion / 4);
         int shift = 2 * (subregion % 4);
-        return (GeonetPoint)(((Data[index] & 0b11 << shift) >> shift));
+        return (GeonetPoint)((Data[index] & 0b11 << shift) >> shift);
     }
 
     public void SetCountrySubregion(byte country, byte subregion, GeonetPoint point)
diff --git a/PKHeX.Core/Saves/Substructures/Gen8/BS/MysteryBlock8b.cs b/PKHeX.Core/Saves/Substructures/Gen8/BS/MysteryBlock8b.cs
index 39b5a8d40..b88ce256a 100644
--- a/PKHeX.Core/Saves/Substructures/Gen8/BS/MysteryBlock8b.cs
+++ b/PKHeX.Core/Saves/Substructures/Gen8/BS/MysteryBlock8b.cs
@@ -113,10 +113,11 @@ private bool[] GetFlags()
             result[i] = GetFlag(i);
         return result;
     }
-    private void SetFlags(IReadOnlyList<bool> value)
+
+    private void SetFlags(ReadOnlySpan<bool> value)
     {
-        ArgumentOutOfRangeException.ThrowIfNotEqual(value.Count, FlagSize);
-        for (int i = 0; i < value.Count; i++)
+        ArgumentOutOfRangeException.ThrowIfNotEqual(value.Length, FlagSize);
+        for (int i = 0; i < value.Length; i++)
             SetFlag(i, value[i]);
     }
     #endregion
diff --git a/PKHeX.Core/Saves/Substructures/Gen8/BS/PoffinSaveData8b.cs b/PKHeX.Core/Saves/Substructures/Gen8/BS/PoffinSaveData8b.cs
index aefb9f154..b2c99d1ce 100644
--- a/PKHeX.Core/Saves/Substructures/Gen8/BS/PoffinSaveData8b.cs
+++ b/PKHeX.Core/Saves/Substructures/Gen8/BS/PoffinSaveData8b.cs
@@ -24,7 +24,7 @@ private static int GetPoffinOffset(int index)
     {
         if ((uint)index >= COUNT_POFFIN)
             throw new ArgumentOutOfRangeException(nameof(index));
-        return (index * Poffin8b.SIZE);
+        return index * Poffin8b.SIZE;
     }
 
     private Memory<byte> GetPoffinSpan(int index) => Raw.Slice(GetPoffinOffset(index), Poffin8b.SIZE);
diff --git a/PKHeX.Core/Saves/Substructures/PokeDex/Zukan8.cs b/PKHeX.Core/Saves/Substructures/PokeDex/Zukan8.cs
index c4046bf53..a585071ba 100644
--- a/PKHeX.Core/Saves/Substructures/PokeDex/Zukan8.cs
+++ b/PKHeX.Core/Saves/Substructures/PokeDex/Zukan8.cs
@@ -500,9 +500,9 @@ public override void SetDex(PKM pk)
 
     public override void SeenNone()
     {
-        Array.Clear(Galar.Data, 0, Galar.Data.Length);
-        Array.Clear(Rigel1.Data, 0, Rigel1.Data.Length);
-        Array.Clear(Rigel2.Data, 0, Rigel2.Data.Length);
+        Galar .Data.AsSpan().Clear();
+        Rigel1.Data.AsSpan().Clear();
+        Rigel2.Data.AsSpan().Clear();
     }
 
     public override void CaughtNone()
diff --git a/PKHeX.Core/Util/ComboItemUtil.cs b/PKHeX.Core/Util/ComboItemUtil.cs
index 7147d206d..fe94bbb2b 100644
--- a/PKHeX.Core/Util/ComboItemUtil.cs
+++ b/PKHeX.Core/Util/ComboItemUtil.cs
@@ -9,7 +9,7 @@ public static partial class Util
 {
     public static List<ComboItem> GetCountryRegionList(string textFile, string lang)
     {
-        string[] inputCSV = GetStringList(textFile);
+        var inputCSV = GetStringList(textFile);
         int index = GeoLocation.GetLanguageIndex(lang);
         var list = GetCBListFromCSV(inputCSV, index);
         if (list.Count > 1)
diff --git a/PKHeX.Core/Util/RandUtil.cs b/PKHeX.Core/Util/RandUtil.cs
index f2fc4790b..6c7ffe471 100644
--- a/PKHeX.Core/Util/RandUtil.cs
+++ b/PKHeX.Core/Util/RandUtil.cs
@@ -8,6 +8,6 @@ public static partial class Util
     public static Random Rand => Random.Shared;
 
     public static uint Rand32() => Rand32(Rand);
-    public static uint Rand32(this Random rnd) => ((uint)rnd.Next(1 << 30) << 2) | (uint)rnd.Next(1 << 2);
+    public static uint Rand32(this Random rnd) => (uint)rnd.NextInt64();
     public static ulong Rand64(this Random rnd) => rnd.Rand32() | ((ulong)rnd.Rand32() << 32);
 }
diff --git a/PKHeX.WinForms/Subforms/Save Editors/Gen5/SAV_Misc5.cs b/PKHeX.WinForms/Subforms/Save Editors/Gen5/SAV_Misc5.cs
index e0dca91b5..0a6b84bae 100644
--- a/PKHeX.WinForms/Subforms/Save Editors/Gen5/SAV_Misc5.cs	
+++ b/PKHeX.WinForms/Subforms/Save Editors/Gen5/SAV_Misc5.cs	
@@ -685,21 +685,21 @@ private void ReadSubway()
         CHK_SWNPCMet.Checked = sw.NPCMet;
 
         // Current Run Checks
-        CHK_SingleSet.Checked = sw.SingleSet == (sw.SinglePast / 7 + 1);
+        CHK_SingleSet.Checked = sw.SingleSet == ((sw.SinglePast / 7) + 1);
         L_SinglePast.Text = CHK_SingleSet.Checked ? "Current" : "Past";
-        CHK_DoubleSet.Checked = sw.DoubleSet == (sw.DoublePast / 7 + 1);
+        CHK_DoubleSet.Checked = sw.DoubleSet == ((sw.DoublePast / 7) + 1);
         L_DoublePast.Text = CHK_DoubleSet.Checked ? "Current" : "Past";
-        CHK_MultiNPCSet.Checked = sw.MultiNPCSet == (sw.MultiNPCPast / 7 + 1);
+        CHK_MultiNPCSet.Checked = sw.MultiNPCSet == ((sw.MultiNPCPast / 7) + 1);
         L_MultiNpcPast.Text = CHK_MultiNPCSet.Checked ? "Current" : "Past";
-        CHK_MultiFriendsSet.Checked = sw.MultiFriendsSet == (sw.MultiFriendsPast / 7 + 1);
+        CHK_MultiFriendsSet.Checked = sw.MultiFriendsSet == ((sw.MultiFriendsPast / 7) + 1);
         L_MultiFriendsPast.Text = CHK_MultiFriendsSet.Checked ? "Current" : "Past";
-        CHK_SuperSingleSet.Checked = sw.SuperSingleSet == (sw.SuperSinglePast / 7 + 1);
+        CHK_SuperSingleSet.Checked = sw.SuperSingleSet == ((sw.SuperSinglePast / 7) + 1);
         L_SSinglePast.Text = CHK_SuperSingleSet.Checked ? "Current" : "Past";
-        CHK_SuperDoubleSet.Checked = sw.SuperDoubleSet == (sw.SuperDoublePast / 7 + 1);
+        CHK_SuperDoubleSet.Checked = sw.SuperDoubleSet == ((sw.SuperDoublePast / 7) + 1);
         L_SDoublePast.Text = CHK_SuperDoubleSet.Checked ? "Current" : "Past";
-        CHK_SuperMultiNPCSet.Checked = sw.SuperMultiNPCSet == (sw.SuperMultiNPCPast / 7 + 1);
+        CHK_SuperMultiNPCSet.Checked = sw.SuperMultiNPCSet == ((sw.SuperMultiNPCPast / 7) + 1);
         L_SMultiNpcPast.Text = CHK_SuperMultiNPCSet.Checked ? "Current" : "Past";
-        CHK_SuperMultiFriendsSet.Checked = sw.SuperMultiFriendsSet == (sw.SuperMultiFriendsPast / 7 + 1);
+        CHK_SuperMultiFriendsSet.Checked = sw.SuperMultiFriendsSet == ((sw.SuperMultiFriendsPast / 7) + 1);
         L_SMultiFriendsPast.Text = CHK_SuperMultiFriendsSet.Checked ? "Current" : "Past";
 
         // Normal
@@ -793,14 +793,14 @@ private void SaveSubway()
         sw.SuperMultiFriendsRecord = (int)NUD_SMultiFriendsRecord.Value;
 
         // Current Run Checks
-        sw.SingleSet = (CHK_SingleSet.Checked ? sw.SinglePast / 7 + 1 : 0);
-        sw.DoubleSet = (CHK_DoubleSet.Checked ? sw.DoublePast / 7 + 1 : 0);
-        sw.MultiNPCSet = (CHK_MultiNPCSet.Checked ? sw.MultiNPCPast / 7 + 1 : 0);
-        sw.MultiFriendsSet = (CHK_MultiFriendsSet.Checked ? sw.MultiFriendsPast / 7 + 1 : 0);
-        sw.SuperSingleSet = (CHK_SuperSingleSet.Checked ? sw.SuperSinglePast / 7 + 1 : 0);
-        sw.SuperDoubleSet = (CHK_SuperDoubleSet.Checked ? sw.SuperDoublePast / 7 + 1 : 0);
-        sw.SuperMultiNPCSet = (CHK_SuperMultiNPCSet.Checked ? sw.SuperMultiNPCPast / 7 + 1 : 0);
-        sw.SuperMultiFriendsSet = (CHK_SuperMultiFriendsSet.Checked ? sw.SuperMultiFriendsPast / 7 + 1 : 0);
+        sw.SingleSet = (CHK_SingleSet.Checked ? (sw.SinglePast / 7) + 1 : 0);
+        sw.DoubleSet = (CHK_DoubleSet.Checked ? (sw.DoublePast / 7) + 1 : 0);
+        sw.MultiNPCSet = (CHK_MultiNPCSet.Checked ? (sw.MultiNPCPast / 7) + 1 : 0);
+        sw.MultiFriendsSet = (CHK_MultiFriendsSet.Checked ? (sw.MultiFriendsPast / 7) + 1 : 0);
+        sw.SuperSingleSet = (CHK_SuperSingleSet.Checked ? (sw.SuperSinglePast / 7) + 1 : 0);
+        sw.SuperDoubleSet = (CHK_SuperDoubleSet.Checked ? (sw.SuperDoublePast / 7) + 1 : 0);
+        sw.SuperMultiNPCSet = (CHK_SuperMultiNPCSet.Checked ? (sw.SuperMultiNPCPast / 7) + 1 : 0);
+        sw.SuperMultiFriendsSet = (CHK_SuperMultiFriendsSet.Checked ? (sw.SuperMultiFriendsPast / 7) + 1 : 0);
     }
 
     private const string ForestCityBinFilter = "Forest City Bin|*.fc5";
diff --git a/PKHeX.WinForms/Util/WinFormsUtil.cs b/PKHeX.WinForms/Util/WinFormsUtil.cs
index adeea5e3b..4f3b14c88 100644
--- a/PKHeX.WinForms/Util/WinFormsUtil.cs
+++ b/PKHeX.WinForms/Util/WinFormsUtil.cs
@@ -264,7 +264,6 @@ public static bool OpenSAVPKMDialog(IEnumerable<string> extensions, out string?
         var sb = new StringBuilder(128);
         foreach (var type in extensions)
             sb.Append($"*.{type};");
-        sb.Append("*.pk");
 
         string supported = sb.ToString();
         using var ofd = new OpenFileDialog();
@@ -275,23 +274,7 @@ public static bool OpenSAVPKMDialog(IEnumerable<string> extensions, out string?
                      "|Binary File|*.bin" +
                      "|Backup File|*.bak";
 
-        // Detect main
-        SaveFile? sav = null;
-        if (DetectSaveFileOnFileOpen)
-        {
-            try
-            {
-                sav = SaveFinder.FindMostRecentSaveFile();
-            }
-            catch (Exception ex)
-            {
-                Error(ex.Message);
-            }
-        }
-
-        if (sav != null)
-            ofd.FileName = sav.Metadata.FileName;
-
+        ofd.FileName = SuggestInitialFileName();
         if (ofd.ShowDialog() != DialogResult.OK)
         {
             path = null;
@@ -302,6 +285,23 @@ public static bool OpenSAVPKMDialog(IEnumerable<string> extensions, out string?
         return true;
     }
 
+    private static string? SuggestInitialFileName()
+    {
+        if (DetectSaveFileOnFileOpen)
+        {
+            try
+            {
+                var sav = SaveFinder.FindMostRecentSaveFile();
+                return sav?.Metadata.FilePath;
+            }
+            catch (Exception ex)
+            {
+                Error(ex.Message);
+            }
+        }
+        return null;
+    }
+
     /// <summary>
     /// Opens a dialog to save a <see cref="PKM"/> file.
     /// </summary>
@@ -312,7 +312,7 @@ public static bool SavePKMDialog(PKM pk)
         string pkx = pk.Extension;
         bool allowEncrypted = pk.Format >= 3 && pkx.StartsWith('p');
         var genericFilter = $"Decrypted PKM File|*.{pkx}" +
-                            (allowEncrypted ? $"|Encrypted PKM File|*.e{pkx[1..]}" : string.Empty) +
+                            (allowEncrypted ? $"|Encrypted PKM File|*.e{pkx.AsSpan(1)}" : string.Empty) +
                             "|Binary File|*.bin" +
                             "|All Files|*.*";
         using var sfd = new SaveFileDialog();
@@ -326,11 +326,11 @@ public static bool SavePKMDialog(PKM pk)
         return true;
     }
 
-    private static void SavePKM(PKM pk, string path, string pkx)
+    private static void SavePKM(PKM pk, string path, ReadOnlySpan<char> pkx)
     {
         SaveBackup(path);
-        string ext = Path.GetExtension(path);
-        var data = $".{pkx}" == ext ? pk.DecryptedPartyData : pk.EncryptedPartyData;
+        var ext = Path.GetExtension(path);
+        var data = ext == $".{pkx}" ? pk.DecryptedPartyData : pk.EncryptedPartyData;
         File.WriteAllBytes(path, data);
     }