Avengers Assemble! is a mythic Enchantment card from Marvel Super Heroes (MSH), collector number 6. Current market price: $1.84 (foil $3.46), TCGplayer market prices via Scryfall.
Flash Heroes you control get +2/+2. At the beginning of each end step, if you attacked with a Hero this turn or a Hero entered the battlefield under your control this turn, draw a card.