for me I guess it's probably four player chess since I haven't played any of the others, or I suck at them
What variants do you play/like?

There are two things bad about bughouse on this website, though.
Every other game ends in an immediate abandonment for whatever reason, and sometimes you face two people who are obviously friends from the same country and exclusively play this variant. And that's an inevitable loss.
Stuff like crazyhouse/bughouse, atomic, fog of war, that kinda thing.
I'm partial to bughouse. It adds a very strange layer of strategy where you might throw everything you've got at a knight so your teammate can checkmate. Very different game, but very fun.