Ty Lee, Artful Acrobat is a uncommon Legendary Creature — Human Performer card from Avatar: The Last Airbender (TLA), collector number 158. Current market price: $0.19 (foil $0.37), TCGplayer market prices via Scryfall.
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) Whenever Ty Lee attacks, you may pay {1}. When you do, target creature can't block this turn.