Gust Walker is a common Creature — Human Wizard card from Amonkhet (AKH), collector number 17. Current market price: $0.05 (foil $0.13), TCGplayer market prices via Scryfall.
You may exert this creature as it attacks. When you do, it gets +1/+1 and gains flying until end of turn. (An exerted creature won't untap during your next untap step.)