Centaur Garden is a uncommon Land card from Odyssey (ODY), collector number 316. Current market price: $2.55 (foil $33.97), TCGplayer market prices via Scryfall.
{T}: Add {G}. This land deals 1 damage to you. Threshold — {G}, {T}, Sacrifice this land: Target creature gets +3/+3 until end of turn. Activate only if there are seven or more cards in your graveyard.