ascension is one of my favs, its a deckbuilder similar to the more popular dominion, but has really cool art (at least with the early expansions, the later ones i dont care for).

basically any game in the oniverse is also good like onirim, sylvion, cyberion, etc. those ones are made for single player but they also have two-player co-op (never tried it though).

tiny epic galaxies is also pretty good if youre looking for a small fast paced space adventure

theres probs better introductions to board gaming lmao and i dont know many co-op games aside from aeons end and spirit island (both of which are very good) but i like to play these personally