Karametra's Acolyte is a uncommon Creature — Human Druid card from Theros (THS), collector number 160. Current market price: $0.38 (foil $0.65), TCGplayer market prices via Scryfall.
{T}: Add an amount of {G} equal to your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)