I had this idea in my head for a while, to the extent that I made an account here specifically just to post it. Introducing... Loyalmons! This is just like the standard game, with one twist: your Pokémon are loyal to you, and will never leave you for any reason. This means no trading. Pokémon You may not use any Pokémon that is only obtainable via Nintendo Event. The purpose of Loyalmons is to see what would happen if you took your game to a desert island. All Pokémon on your team must be obtainable in the same game. For instance, using Tornadus and Thundurus on the same team is banned. To make things a little more varied, you may pick any game from ADV or DPP or BW, but regardless of which you pick, all BW mechanics will be used. Pokémon that evolve via a trade, such as Alakazam, Politoed, Accelgor, etc. may not be used. Their pre-evolved forms, however, may be used. On a similar note, Milotic is banned on BW teams, but is legal on ADV or DPP teams. If you can't obtain both Pokémon on a single playthrough, then you can't have both. Using two starters, for example, is banned. Moves Moves obtained via Nintendo Event are banned, unless the event can be found in-game, such as the Extremespeed Dratini in HGSS. Egg moves are legal only if there is a compatible father obtainable in your game. In pre-BW teams, TM moves may only be used once, except for those that can be purchased at the Department Store, won at the Game Corner, found via Pickup, etc. If a TM is obtained multiple times, then it may be used that many times. For instance, Return is found twice in RSE. No intergenerational movesets. A move that can only be obtained in ADV and a move that can only be obtained in DPP is banned. Move Tutor moves that can only be taught once in-game can only be used once per team. Abilities Hidden Abilities are banned, unless they can be obtained in-game, such as Musharna and Darmanitan. Gen III moves with Gen IV abilities is banned, even if the Pokémon is capable of evolution. Items Items that are found on the ground or obtained from NPCs may only be used as many times as you obtain them. The only unlimited items are those that can be purchased, found via Pickup, or held by wild Pokémon. This really isn't an issue for any competitive-use items in BW though. Stats Though incredibly unlikely, if Nintendo and Game Freak ever make a game where there are no Pokémon found in-game that give EVs of a certain type, then those EVs cannot be used on teams from that game. Similarly, if they ever make new Natures, these natures cannot be used in combination with things from other games.