Port of Karfell is a uncommon Land card from The Lost Caverns of Ixalan Commander (LCC), collector number 347. Current market price: $0.26, TCGplayer market prices via Scryfall.
This land enters tapped. {T}: Add {U}. {3}{U}{B}{B}, {T}, Sacrifice this land: Mill four cards, then return a creature card from your graveyard to the battlefield tapped. (To mill a card, put the top card of your library into your graveyard.)