Cream of the Crop is a rare Enchantment card from Lorwyn Eclipsed Commander (ECC), collector number 102. Current market price: $0.39, TCGplayer market prices via Scryfall.
Whenever a creature you control enters, you may look at the top X cards of your library, where X is that creature's power. If you do, put one of those cards on top of your library and the rest on the bottom of your library in any order.