Ziatora's Proving Ground is a rare Land — Swamp Mountain Forest card from Streets of New Capenna Promos (PSNC), collector number 261p. Current market price: $14.51 (foil $10.12), TCGplayer market prices via Scryfall.
({T}: Add {B}, {R}, or {G}.) This land enters tapped. Cycling {3} ({3}, Discard this card: Draw a card.)