Goof Troop is barely playable without a 2nd player. A heck of a lot of fun!
Kirby Super Star has a co-op mode that enhances the base game. Played trough it with my bro a time or two
Mystical Ninja is a great game, one or two player
Pocky & Rocky Probably my pick for my favorite 2 player SNES game
Super Bomberman is a great entry in the Bomberman series. There are like four of these on the SNES and a newer version on the Switch
Super Smash TV is probably better in the arcade but the SNES version is the definitive home conversion.
Zombies Ate My Neighbors A must own for SNES collectors. Incredibly fun game.