Greenbelt Guardian is a uncommon Creature — Elf Ranger card from Aetherdrift (DFT), collector number 164. Current market price: $0.20 (foil $0.18), TCGplayer market prices via Scryfall.
{G}: Target creature gains trample until end of turn. Exhaust — {3}{G}: Put three +1/+1 counters on this creature. (Activate each exhaust ability only once.)