This should be a handy resource for many TAG projects. Co-optimus is a website/community dedicated to the exploration of coop games. As the blurb says “every game listed on our site has some form of cooperative gameplay element. Our job is to bring you the most comprehensive list of games that support co-op play, and let you know what that experience is like!”
One the interesting things here is their working definition of co-op:
“A co-op game is a game where two or more players work together to accomplish a goal against AI opponents. Ideally the game will feature a strong story in which both players take part of. Co-Op can be online over the internet, offline on the same console, or via a LAN or Wireless Network. We do not consider team based games as co-op where players face off against another team of human players.”
The line between team-based PvE and PvP (as its defined in the MMOG world) is pretty thin sometimes but the distinction speaks well to the difference in design emphasis and how very difficult it has been to create very successful co-op games (or co-op vs AI games).