Swarm Guildmage is a uncommon Creature — Elf Shaman card from Guilds of Ravnica (GRN), collector number 201. Current market price: $0.14 (foil $0.32), TCGplayer market prices via Scryfall.
{4}{B}, {T}: Creatures you control get +1/+0 and gain menace until end of turn. (They can't be blocked except by two or more creatures.) {1}{G}, {T}: You gain 2 life.