

Since you mentioned platformers, Rayman Origins might be worth a look. It’s a 2D platformer from 2011 so it doesn’t require a lot of power, levels take a few minutes to complete which makes it perfect for short sessions and it has local co-op (up to 4 players).
I tried it recently on my desktop (Pop!_OS, ubuntu based) and Steam Deck, played without issues on both of them.












Older games are purely singleplayer, multi is something they leaned on later on. For PC Rayman Legends also supports local co-op, I believe. This one however is only available on Steam and requires Uplay account or linking your Steam to it. Origins is available on both Steam and GOG - I can confirm the latter version does not require any additional accounts or services.
Finally, there’s Rayman Raving Rabbids but that’s more of a mini-game compilation/party game rather than a platformer. It also has multiplayer.