Secrets of Paradise is a common Conspiracy card from Conspiracy (CNS), collector number 10. Current market price: $0.14 (foil $0.64), TCGplayer market prices via Scryfall.
Hidden agenda (Start the game with this conspiracy face down in the command zone and secretly choose a card name. You may turn this conspiracy face up any time and reveal that name.) Creatures you control with the chosen name have "{T}: Add one mana of any color."