Definitely Official & Online:
* Pokémon GO: A location-based augmented reality game that lets you catch Pokémon in the real world. It's free-to-play with in-app purchases.
* Pokémon UNITE: A MOBA (Multiplayer Online Battle Arena) style game with 5v5 team battles. It's free-to-play with in-app purchases.
* Pokémon Masters EX: A mobile game where you team up with trainers from past Pokémon games to battle others. It's free-to-play with in-app purchases.
* Pokémon Trading Card Game Online: A free-to-play digital version of the Pokémon Trading Card Game. You can build decks, play against others, and participate in events.
Official, but Not Primarily Online:
* Pokémon Sword & Shield/Scarlet & Violet: While these games are primarily single-player RPGs, they have online features like trading, battling, and interacting with other players in the same game world.
Not Officially Developed by Nintendo/Game Freak:
* Pokémon Showdown: A popular online simulator where you can battle with other players using teams you build. This isn't officially developed by Nintendo, but it uses data from official games and is widely considered a legitimate way to play Pokémon competitively.
Important Notes:
* Many games that claim to be "Pokémon" online are unofficial and may be scams or infringe on copyrights. Always check the game developer and make sure it's a legitimate Pokémon game.
* The quality and availability of online features may vary depending on the specific game and the platform.
In short: There are several official Pokémon online games available, but the best option for you will depend on what kind of gameplay you're looking for.