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.
Honorable mentions: Mantis Falls for 2p semi-coop. You have to work together to get to the end of the road but there is a 50% chance that your partner is an assassin biding his time.
Shipwreck Arcana is fantastic, I love that game. It is kinda hard for me to find people with the right mindset for this logic+deduction style game but when you find the right people this game shines bright. So simple yet so much fun.