Team Avatar is a uncommon Enchantment card from Avatar: The Last Airbender (TLA), collector number 38. Current market price: $0.17 (foil $0.29), TCGplayer market prices via Scryfall.
Whenever a creature you control attacks alone, it gets +X/+X until end of turn, where X is the number of creatures you control. {2}{W}, Discard this card: It deals damage equal to the number of creatures you control to target creature.