I’d have difficulty naming ten, since I usually stick to single player games. Mainly the Sonic and Halo games. Ikaruga, as well. Metal Slug, Gunstar & Guardian Heroes could be fun too.
Since you mentioned Contra, I used to play a game called Probotector co-op. It was a rebranded version of one of the Contra games for PAL Megadrives. The human characters were replaced by robots.
I never got heavily into Gears of War and didn’t have the opportunity to try ICO in co-op mode.