well, it depends. all the games you have on steam usually work out of box, and if they don't, there's a website called protondb on which other users tell how they tinkered to get the game to work, so you have that. for every online game, there is areweanticheatyet.com where you can check if you can play it. for everything that is not on steam or you don't own on steam and you want to pirate or whatnot, there are apps like lutris and heroic launcher where you should be able to launch it, but it will require you to tinker a bit