Human: Fall Flat | 1+ Players
Daft slapstick physics platformer. Overcoming obstacles and puzzles together is rewarding, and the level design encourages multiple playthroughs and fun sequence breaking with teamwork.
Chariot | 2 Players
Another physics based platformer about dragging a coffin to its final resting spot and using it for platforming. Requires a lot of finesse and co-operation. Challenging, maybe doesn't shake things up enough as you go through and so can feel a lil samey after a while but good fun.
Treasure Treasure: Fortress Forage | 2 Players
Nearly a decade since I played this but I remember enjoying it! Short free puzzle platformer where each player has their own abilities, gotta work together to find all the treasures.
All To Get Her | 2 Players
Oh hey speaking about good puzzle platformers where every character has their own abilities, vgperson's All To Get Her is really good if you both like working together n solving puzzles!
Here's a link
http://vgperson.com/games/alltogether.htmOvercooked | 2-4 Players
Really good experience if you like to aim for perfection. Every level is a new challenge that you can get wrong, but then you get to work together to formulate a strategy, execute it and keep iterating it until you get 3*.
Pikmin 3 Challenge Mode | 2 Players
I like this for the same reason i like Overcooked in that you get to blast away together at a stage until you get the perfect clear! It records all your playthrough on the touchscreen map so you can analyse where you went wrong and how to improve for next time. The DLC map pack is also p good. Don't know if you have a Wii U though.
Divinity: Original Sin 2 |2-4 Players
Much more of a longform experience but great if you kinda wanna exist in the same world together. Works really well co-op in that you can completely go off and do your own stuff and seamlessly join each other's battles. I've got a few issues with how it handles player death in co-op mode etc but it's neat and there's not a lotta co-op rpgs like it