Predator's Gambit is a common Enchantment — Aura card from Avacyn Restored (AVR), collector number 117. Current market price: $0.17 (foil $0.18), TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature gets +2/+1. Enchanted creature has intimidate as long as its controller controls no other creatures. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)