What's a good, fun co-op game?

Basically just after any sort of co-op game that has some sort of progression or leveling or that sort of thing.
Co-op games I've already played/play atm are:
Payday 2 - Wow - Minecraft - Terraria - Starbound - Borderlands 2 - Aion - Warframe - Dayz - Dungeon Defenders - Simcity - Rift

League of Lengends- www.pvp.net

Conquer Online

Have you tried resident evil 6?!

or maybe command and conquer?!

just lay low and do BORDERLANDS 2 MAN! It's my life

Borderlands 2!