Voltaic Brawler is a uncommon Creature — Human Warrior card from Kaladesh (KLD), collector number 189. Current market price: $0.17 (foil $0.28), TCGplayer market prices via Scryfall.
When this creature enters, you get {E}{E} (two energy counters). Whenever this creature attacks, you may pay {E}. If you do, it gets +1/+1 and gains trample until end of turn.