Restructured the project structure back to the way it was, there's no reasonable way to split the modules

src/NadekoBot/Db/Extensions/ReminderExtensions.cs

@@ -0,0 +1,23 @@
+#nullable disable
+using Microsoft.EntityFrameworkCore;
+using Nadeko.Bot.Db.Models;
+
+namespace NadekoBot.Db;
+
+public static class ReminderExtensions
+{
+    public static IEnumerable<Reminder> GetIncludedReminders(
+        this DbSet<Reminder> reminders,
+        IEnumerable<ulong> guildIds)
+        => reminders.AsQueryable().Where(x => guildIds.Contains(x.ServerId) || x.ServerId == 0).ToList();
+
+    public static IEnumerable<Reminder> RemindersFor(this DbSet<Reminder> reminders, ulong userId, int page)
+        => reminders.AsQueryable().Where(x => x.UserId == userId).OrderBy(x => x.DateAdded).Skip(page * 10).Take(10);
+
+    public static IEnumerable<Reminder> RemindersForServer(this DbSet<Reminder> reminders, ulong serverId, int page)
+        => reminders.AsQueryable()
+                    .Where(x => x.ServerId == serverId)
+                    .OrderBy(x => x.DateAdded)
+                    .Skip(page * 10)
+                    .Take(10);
+}