Castle Garenbrig is a rare Land card from The List (PLST), collector number ELD-240. Current market price: $11.89, TCGplayer market prices via Scryfall.
This land enters tapped unless you control a Forest. {T}: Add {G}. {2}{G}{G}, {T}: Add six {G}. Spend this mana only to cast creature spells or activate abilities of creatures.