Planeswalker's Favor is a rare Enchantment card from Planeshift (PLS), collector number 86. Current market price: $0.39 (foil $16.49), TCGplayer market prices via Scryfall.
{3}{G}: Target opponent reveals a card at random from their hand. Target creature gets +X/+X until end of turn, where X is the revealed card's mana value.