Anafenza, the Foremost is a mythic Legendary Creature — Human Soldier card from Khans of Tarkir (KTK), collector number 163. Current market price: $0.58 (foil $3.39), TCGplayer market prices via Scryfall.
Whenever Anafenza attacks, put a +1/+1 counter on another target tapped creature you control. If a nontoken creature an opponent owns would die or a creature card not on the battlefield would be put into an opponent's graveyard, exile that card instead.