Just grabbed Six Days in Fallujah today (MilSim) and got Crime Boss: Rockay City for €2 last week. Both are good fun and support co-op play.

Here's my current wishlist though bear in mind that some games were added a long time ago or they're just on there to follow for now (to see if they get better or to maybe grab them during a sale) https://store.steampowered.com/wishlist/id/cybergrinder/