diff --git a/PKHeX.Core/Legality/Encounters/Data/EncounterEvent.cs b/PKHeX.Core/Legality/Encounters/Data/EncounterEvent.cs
index a92068aec..964c5989c 100644
--- a/PKHeX.Core/Legality/Encounters/Data/EncounterEvent.cs
+++ b/PKHeX.Core/Legality/Encounters/Data/EncounterEvent.cs
@@ -33,52 +33,73 @@ namespace PKHeX.Core
         /// <summary>Indicates if the databases are initialized.</summary>
         public static bool Initialized => MGDB_G3.Count != 0;
 
-        private static HashSet<PCD> GetPCDDB(byte[] bin) => new(ArrayUtil.EnumerateSplit(bin, PCD.Size).Select(d => new PCD(d)));
+        private static PCD[] GetPCDDB(byte[] bin) => Get(bin, PCD.Size, d => new PCD(d));
+        private static PGF[] GetPGFDB(byte[] bin) => Get(bin, PGF.Size, d => new PGF(d));
 
-        private static HashSet<PGF> GetPGFDB(byte[] bin) => new(ArrayUtil.EnumerateSplit(bin, PGF.Size).Select(d => new PGF(d)));
+        private static WC6[] GetWC6DB(byte[] wc6bin, byte[] wc6full) => WC6Full.GetArray(wc6full, wc6bin);
+        private static WC7[] GetWC7DB(byte[] wc7bin, byte[] wc7full) => WC7Full.GetArray(wc7full, wc7bin);
 
-        private static HashSet<WC6> GetWC6DB(byte[] wc6bin, byte[] wc6full) => new(
-            ArrayUtil.EnumerateSplit(wc6full, WC6Full.Size).Select(d => new WC6Full(d).Gift)
-            .Concat(ArrayUtil.EnumerateSplit(wc6bin, WC6.Size).Select(d => new WC6(d))));
+        private static WB7[] GetWB7DB(byte[] bin) => Get(bin, WB7.SizeFull, d => new WB7(d));
+        private static WC8[] GetWC8DB(byte[] bin) => Get(bin, WC8.Size, d => new WC8(d));
 
-        private static HashSet<WC7> GetWC7DB(byte[] wc7bin, byte[] wc7full) => new(
-            ArrayUtil.EnumerateSplit(wc7full, WC7Full.Size).Select(d => new WC7Full(d).Gift)
-            .Concat(ArrayUtil.EnumerateSplit(wc7bin, WC7.Size).Select(d => new WC7(d))));
-
-        private static HashSet<WB7> GetWB7DB(byte[] wc7full) => new(ArrayUtil.EnumerateSplit(wc7full, WB7.SizeFull).Select(d => new WB7(d)));
-
-        private static HashSet<WC8> GetWC8DB(byte[] wc8bin) =>
-            new(ArrayUtil.EnumerateSplit(wc8bin, WC8.Size).Select(d => new WC8(d)));
+        private static T[] Get<T>(byte[] bin, int size, Func<byte[], T> ctor)
+        {
+            var result = new T[bin.Length / size];
+            System.Diagnostics.Debug.Assert(result.Length * size == bin.Length);
+            for (int i = 0; i < result.Length; i++)
+            {
+                var offset = i * size;
+                var slice = bin.Slice(offset, size);
+                result[i] = ctor(slice);
+            }
+            return result;
+        }
 
         public static void RefreshMGDB(params string[] paths)
         {
-            var g4 = GetPCDDB(Util.GetBinaryResource("wc4.pkl"));
-            var g5 = GetPGFDB(Util.GetBinaryResource("pgf.pkl"));
-            var g6 = GetWC6DB(Util.GetBinaryResource("wc6.pkl"), Util.GetBinaryResource("wc6full.pkl"));
-            var g7 = GetWC7DB(Util.GetBinaryResource("wc7.pkl"), Util.GetBinaryResource("wc7full.pkl"));
-            var b7 = GetWB7DB(Util.GetBinaryResource("wb7full.pkl"));
-            var g8 = GetWC8DB(Util.GetBinaryResource("wc8.pkl"));
+            ICollection<PCD> g4 = GetPCDDB(Util.GetBinaryResource("wc4.pkl"));
+            ICollection<PGF> g5 = GetPGFDB(Util.GetBinaryResource("pgf.pkl"));
+            ICollection<WC6> g6 = GetWC6DB(Util.GetBinaryResource("wc6.pkl"), Util.GetBinaryResource("wc6full.pkl"));
+            ICollection<WC7> g7 = GetWC7DB(Util.GetBinaryResource("wc7.pkl"), Util.GetBinaryResource("wc7full.pkl"));
+            ICollection<WB7> b7 = GetWB7DB(Util.GetBinaryResource("wb7full.pkl"));
+            ICollection<WC8> g8 = GetWC8DB(Util.GetBinaryResource("wc8.pkl"));
 
             foreach (var gift in paths.Where(Directory.Exists).SelectMany(MysteryUtil.GetGiftsFromFolder))
             {
+                static void AddOrExpand<T>(ref ICollection<T> arr, T obj)
+                {
+                    if (arr is HashSet<T>)
+                        arr.Add(obj);
+                    else
+                        arr = new HashSet<T>(arr) {obj};
+                }
                 switch (gift)
                 {
-                    case PCD pcd: g4.Add(pcd); continue;
-                    case PGF pgf: g5.Add(pgf); continue;
-                    case WC6 wc6: g6.Add(wc6); continue;
-                    case WC7 wc7: g7.Add(wc7); continue;
-                    case WB7 wb7: b7.Add(wb7); continue;
-                    case WC8 wc8: g8.Add(wc8); continue;
+                    case PCD pcd: AddOrExpand(ref g4, pcd); continue;
+                    case PGF pgf: AddOrExpand(ref g5, pgf); continue;
+                    case WC6 wc6: AddOrExpand(ref g6, wc6); continue;
+                    case WC7 wc7: AddOrExpand(ref g7, wc7); continue;
+                    case WB7 wb7: AddOrExpand(ref b7, wb7); continue;
+                    case WC8 wc8: AddOrExpand(ref g8, wc8); continue;
                 }
             }
 
+            static T[] SetArray<T>(ICollection<T> arr)
+            {
+                if (arr is T[] x)
+                    return x;
+                var result = new T[arr.Count];
+                ((HashSet<T>)arr).CopyTo(result, 0);
+                return result;
+            }
+
             MGDB_G3 = Encounter_WC3; // hardcoded
-            MGDB_G4 = g4.ToArray();
-            MGDB_G5 = g5.ToArray();
-            MGDB_G6 = g6.ToArray();
-            MGDB_G7 = g7.ToArray();
-            MGDB_G7GG = b7.ToArray();
-            MGDB_G8 = g8.ToArray();
+            MGDB_G4 = SetArray(g4);
+            MGDB_G5 = SetArray(g5);
+            MGDB_G6 = SetArray(g6);
+            MGDB_G7 = SetArray(g7);
+            MGDB_G7GG = SetArray(b7);
+            MGDB_G8 = SetArray(g8);
         }
 
         public static IEnumerable<MysteryGift> GetAllEvents(bool sorted = true)
diff --git a/PKHeX.Core/Legality/Encounters/Generator/Specific/MysteryGiftGenerator.cs b/PKHeX.Core/Legality/Encounters/Generator/Specific/MysteryGiftGenerator.cs
index ddefd5e57..6fe691bc2 100644
--- a/PKHeX.Core/Legality/Encounters/Generator/Specific/MysteryGiftGenerator.cs
+++ b/PKHeX.Core/Legality/Encounters/Generator/Specific/MysteryGiftGenerator.cs
@@ -32,7 +32,7 @@ namespace PKHeX.Core
             return GetMatchingGifts(pkm, table, chain);
         }
 
-        private static IReadOnlyList<MysteryGift> GetTable(int generation, PKM pkm) => generation switch
+        private static IReadOnlyCollection<MysteryGift> GetTable(int generation, PKM pkm) => generation switch
         {
             3 => MGDB_G3,
             4 => MGDB_G4,
@@ -43,7 +43,7 @@ namespace PKHeX.Core
             _ => Array.Empty<MysteryGift>()
         };
 
-        private static IEnumerable<MysteryGift> GetMatchingPCD(PKM pkm, IReadOnlyList<PCD> DB, IReadOnlyList<DexLevel> chain)
+        private static IEnumerable<MysteryGift> GetMatchingPCD(PKM pkm, IReadOnlyCollection<PCD> DB, IReadOnlyList<DexLevel> chain)
         {
             if (PGT.IsRangerManaphy(pkm))
             {
@@ -55,7 +55,7 @@ namespace PKHeX.Core
                 yield return g;
         }
 
-        private static IEnumerable<MysteryGift> GetMatchingGifts(PKM pkm, IReadOnlyList<MysteryGift> DB, IReadOnlyList<DexLevel> chain)
+        private static IEnumerable<MysteryGift> GetMatchingGifts(PKM pkm, IReadOnlyCollection<MysteryGift> DB, IReadOnlyList<DexLevel> chain)
         {
             foreach (var mg in DB)
             {
diff --git a/PKHeX.Core/MysteryGifts/WC6Full.cs b/PKHeX.Core/MysteryGifts/WC6Full.cs
index 7e9c6bc5e..5593215cb 100644
--- a/PKHeX.Core/MysteryGifts/WC6Full.cs
+++ b/PKHeX.Core/MysteryGifts/WC6Full.cs
@@ -5,6 +5,7 @@ namespace PKHeX.Core
     public sealed class WC6Full
     {
         public const int Size = 0x310;
+        private const int GiftStart = Size - WC6.Size;
         public readonly byte[] Data;
         public readonly WC6 Gift;
 
@@ -14,7 +15,7 @@ namespace PKHeX.Core
         public WC6Full(byte[] data)
         {
             Data = data;
-            var wc6 = data.SliceEnd(Size - WC6.Size);
+            var wc6 = data.SliceEnd(GiftStart);
             Gift = new WC6(wc6);
             var now = DateTime.Now;
             Gift.RawDate = WC6.SetDate((uint)now.Year, (uint)now.Month, (uint)now.Day);
@@ -22,5 +23,36 @@ namespace PKHeX.Core
             Gift.RestrictVersion = RestrictVersion;
             Gift.RestrictLanguage = RestrictLanguage;
         }
+        public static WC6[] GetArray(byte[] WC6Full, byte[] data)
+        {
+            var countfull = WC6Full.Length / Size;
+            var countgift = data.Length / WC6.Size;
+            var result = new WC6[countfull + countgift];
+
+            var now = DateTime.Now;
+            for (int i = 0; i < countfull; i++)
+                result[i] = ReadWC6(WC6Full, i * Size, now);
+            for (int i = 0; i < countgift; i++)
+                result[i + countfull] = ReadWC6Only(data, i * WC6.Size);
+
+            return result;
+        }
+
+        private static WC6 ReadWC6(byte[] data, int ofs, DateTime date)
+        {
+            var slice = data.Slice(ofs + GiftStart, WC6.Size);
+            return new WC6(slice)
+            {
+                RestrictVersion = data[ofs],
+                RestrictLanguage = data[ofs + 0x1FF],
+                RawDate = WC6.SetDate((uint)date.Year, (uint)date.Month, (uint)date.Day)
+            };
+        }
+
+        private static WC6 ReadWC6Only(byte[] data, int ofs)
+        {
+            var slice = data.Slice(ofs, WC6.Size);
+            return new WC6(slice);
+        }
     }
 }
\ No newline at end of file
diff --git a/PKHeX.Core/MysteryGifts/WC7Full.cs b/PKHeX.Core/MysteryGifts/WC7Full.cs
index d9f82dfee..e6db44047 100644
--- a/PKHeX.Core/MysteryGifts/WC7Full.cs
+++ b/PKHeX.Core/MysteryGifts/WC7Full.cs
@@ -5,6 +5,7 @@ namespace PKHeX.Core
     public sealed class WC7Full
     {
         public const int Size = 0x310;
+        private const int GiftStart = Size - WC7.Size;
         public readonly byte[] Data;
         public readonly WC7 Gift;
 
@@ -14,7 +15,7 @@ namespace PKHeX.Core
         public WC7Full(byte[] data)
         {
             Data = data;
-            var wc7 = data.SliceEnd(Size - WC7.Size);
+            var wc7 = data.SliceEnd(GiftStart);
             Gift = new WC7(wc7);
             var now = DateTime.Now;
             Gift.RawDate = WC7.SetDate((uint)now.Year, (uint)now.Month, (uint)now.Day);
@@ -22,5 +23,37 @@ namespace PKHeX.Core
             Gift.RestrictVersion = RestrictVersion;
             Gift.RestrictLanguage = RestrictLanguage;
         }
+
+        public static WC7[] GetArray(byte[] wc7Full, byte[] data)
+        {
+            var countfull = wc7Full.Length / Size;
+            var countgift = data.Length / WC7.Size;
+            var result = new WC7[countfull + countgift];
+
+            var now = DateTime.Now;
+            for (int i = 0; i < countfull; i++)
+                result[i] = ReadWC7(wc7Full, i * Size, now);
+            for (int i = 0; i < countgift; i++)
+                result[i + countfull] = ReadWC7Only(data, i * WC7.Size);
+
+            return result;
+        }
+
+        private static WC7 ReadWC7(byte[] data, int ofs, DateTime date)
+        {
+            var slice = data.Slice(ofs + GiftStart, WC7.Size);
+            return new WC7(slice)
+            {
+                RestrictVersion = data[ofs],
+                RestrictLanguage = data[ofs + 0x1FF],
+                RawDate = WC7.SetDate((uint) date.Year, (uint) date.Month, (uint) date.Day)
+            };
+        }
+
+        private static WC7 ReadWC7Only(byte[] data, int ofs)
+        {
+            var slice = data.Slice(ofs, WC7.Size);
+            return new WC7(slice);
+        }
     }
 }
\ No newline at end of file