Marvel Legendary: Guardians of the Galaxy

This is a new expansion, which consists of 100 new cards, out of which 5 are new heroes, 2 new villain groups and 2 Masterminds. The art in the game is all original.

From the announcement:

Guardians of the Galaxy is easy to learn and features incredible original artwork of Marvel Heroes and Villains. Players can create their own powerful combos on the fly, combining their hero's awesome abilities to take down the Marvel Masterminds. Legendary Guardians is a fast paced game full of strategy, depth, fun and replay-ability. Innovative Mastermind mechanics allow the game itself to fight back against the players.