Adriana, Captain of the Guard is a rare Legendary Creature — Human Knight card from Dominaria United Commander (DMC), collector number 139. Current market price: $0.38, TCGplayer market prices via Scryfall.
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.) Other creatures you control have melee. (If a creature has multiple instances of melee, each triggers separately.)