Maestros Theater is a common Land card from Streets of New Capenna (SNC), collector number 251. Current market price: $0.33 (foil $0.44), TCGplayer market prices via Scryfall.
When this land enters, sacrifice it. When you do, search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle and you gain 1 life.