Kefnet the Mindful is a mythic Legendary Creature — God card from Amonkhet (AKH), collector number 59. Current market price: $0.49 (foil $8.22), TCGplayer market prices via Scryfall.
Flying, indestructible Kefnet can't attack or block unless you have seven or more cards in hand. {3}{U}: Draw a card, then you may return a land you control to its owner's hand.