My favorite TTRPG is the homebrew system I made myself!
But besides that I’ve played D&D 3, 3.5, 4, 5, 5.5, Pathfinder 1 and 2, CoC, GURPS, Dungeon Crawl Classics, Traveler, Star Wars 5e, and Mini Six. I’m familiar with a lot of others through podcasts, like Paranoia, Toon, VtM, Fate Core, Fiasco, and Over The Edge.
Cult of the Lamb is a 2 player coop RPG with roguelite gameplay! I’ve only played single player though so I can’t speak to the coop.
One of my favorites is Rogue Heroes: Ruins of Tasos. It’s a Zeldalike roguelite with city building and a bunch of player classes. I had a blast with this one. Looks like you need a custom GE-Proton for this.
Also a shoutout to Rabbit & Steel, which is a 2D MMO raid simulator roguelike.