Muzzio's Preparations is a common Conspiracy card from Conspiracy (CNS), collector number 7. Current market price: $0.10 (foil $0.60), 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.) Each creature you control with the chosen name enters with an additional +1/+1 counter on it.