diff --git a/osu.Game/Extensions/CollectionExtensions.cs b/osu.Game/Extensions/CollectionExtensions.cs
new file mode 100644
index 0000000000..473dc4b8f4
--- /dev/null
+++ b/osu.Game/Extensions/CollectionExtensions.cs
@@ -0,0 +1,22 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+
+namespace osu.Game.Extensions
+{
+    public static class CollectionExtensions
+    {
+        public static void AddRange<T>(this ICollection<T> collection, IEnumerable<T> items)
+        {
+            // List<T> has a potentially more optimal path to adding a range.
+            if (collection is List<T> list)
+                list.AddRange(items);
+            else
+            {
+                foreach (T obj in items)
+                    collection.Add(obj);
+            }
+        }
+    }
+}
diff --git a/osu.Game/Stores/BeatmapImporter.cs b/osu.Game/Stores/BeatmapImporter.cs
index dad2b29dd0..32f0cd3d7a 100644
--- a/osu.Game/Stores/BeatmapImporter.cs
+++ b/osu.Game/Stores/BeatmapImporter.cs
@@ -7,7 +7,6 @@ using System.IO;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
-using NuGet.Packaging;
 using osu.Framework.Audio.Track;
 using osu.Framework.Extensions;
 using osu.Framework.Extensions.IEnumerableExtensions;
diff --git a/osu.Game/Stores/RealmArchiveModelImporter.cs b/osu.Game/Stores/RealmArchiveModelImporter.cs
index 5b8c73b218..6370d4ebe4 100644
--- a/osu.Game/Stores/RealmArchiveModelImporter.cs
+++ b/osu.Game/Stores/RealmArchiveModelImporter.cs
@@ -8,7 +8,6 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Humanizer;
-using NuGet.Packaging;
 using osu.Framework.Extensions;
 using osu.Framework.Extensions.IEnumerableExtensions;
 using osu.Framework.Logging;