Undercity Informer is a uncommon Creature — Human Rogue card from Gatecrash (GTC), collector number 82. Current market price: $0.28 (foil $0.48), TCGplayer market prices via Scryfall.
{1}, Sacrifice a creature: Target player reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.