Prowess of the Fair is a uncommon Kindred Enchantment — Elf card from Lorwyn (LRW), collector number 136. Current market price: $3.78 (foil $33.88), TCGplayer market prices via Scryfall.
Whenever another nontoken Elf is put into your graveyard from the battlefield, you may create a 1/1 green Elf Warrior creature token.