

Dolphin does online multiplayer for game cube, and I think also wii
There’s also a neat back way to use steam for it too. You need a game that supports steam’s remote play together, and you can replace the install files with an emulator, rename the emulator .exe to match the game you replaced and launch it with steam. I might be missing part of the method, so googling might be necessary, but I’ve done this with a few friends before with xbox emulation and it worked great.
Edit: found the forum post I used at the time!
https://steamcommunity.com/groups/homestream/discussions/3/1643178512758489324/



I used to use a 3rd party reddit app, and refused to use the awful 1st party app when they made it mandatory. So I deleted my account, and came here instead!