Rundvelt Hordemaster is a rare Creature — Goblin Warrior card from Dominaria United Promos (PDMU), collector number 142p. Current market price: $6.09 (foil $6.20), TCGplayer market prices via Scryfall.
Other Goblins you control get +1/+1. Whenever this creature or another Goblin you control dies, exile the top card of your library. If it's a Goblin creature card, you may cast that card until the end of your next turn.