Glory-Bound Initiate is a rare Creature — Human Warrior card from Amonkhet (AKH), collector number 16. Current market price: $0.12 (foil $0.55), TCGplayer market prices via Scryfall.
You may exert this creature as it attacks. When you do, it gets +1/+3 and gains lifelink until end of turn. (An exerted creature won't untap during your next untap step.)