Meltstrider's Resolve is a uncommon Enchantment — Aura card from Edge of Eternities (EOE), collector number 199. Current market price: $0.35 (foil $0.39), TCGplayer market prices via Scryfall.
Enchant creature you control When this Aura enters, enchanted creature fights up to one target creature an opponent controls. (Each deals damage equal to its power to the other.) Enchanted creature gets +0/+2 and can't be blocked by more than one creature.