lethal company probably has the biggest bang for your buck if you're looking for a funny co-op horror game. easy to pick up, pretty cheap, doesn't take itself too seriously... it's a good time!
Overcooked! 2
huge replayability with a sense of progression. good for completionists but also non-completionists
The Outlast Trials
the scariest part is when a man walks at you with his cock swangin
Castle Crashers
online co-op is actually super good...? im on the US's west coast and i played with someone in the middle of the country, someone in the UK, someone in sweden, and the game buffered badly at first but was completely fine for the entire rest of the game
Uno
Smithworks
it is undeniably free
Devour
getting-your-ass-kicked simulator
PlateUp!
genuinely so cute and one of the only games on this list i'd recommend you still play with less than 4
Phasmophobia
i booted up phasmo recently and GODDDD it's harder than i remember. not as easy to pick up as it used to be