Traditional Battles:
* Most Main Series Games: Almost every Pokemon game allows you to battle a friend using a link cable, local wireless, or online connectivity. You can trade Pokemon and challenge each other to show off your skills.
* Pokemon Stadium/Colosseum/XD: These games allow you to battle against a friend using the Game Boy Advance link cable and even enjoy special "Double Battles" where two trainers battle against two other trainers.
Other 2-Player Options:
* Pokemon Mystery Dungeon Series: Some games in this series allow you to play through the main story in cooperative mode, where both players control separate Pokemon.
* Pokemon Rumble Rush: This mobile game offers a "Co-op Mode" where two players can team up to defeat enemies together.
* Pokemon Unite: This MOBA game lets you team up with a friend and battle other players online.
Keep in mind:
* Not all games have all features mentioned above. For example, not every main series game has online connectivity.
* Some features require specific hardware or online subscriptions.
It's best to check the specific details of the Pokemon game you are interested in to find out what 2-player options are available.