I would be curious about your favorite coop games. I often find them a big lacking, often being a bit unbalanced. An example is Battle for Hogwarts, where one game can be a walk in the park and another absolutely impossible and rarely is there a balanced match.
Hanabi, for sure. Avoids quarterbacking through hidden info, lots of levels of difficulty, and genuinely beautiful (E: in the deluxe edition, at least)
I love this as a test of communication. Because its always different with each group