Goblin Rabblemaster is a rare Creature — Goblin Warrior card from Duel Decks: Merfolk vs. Goblins (DDT), collector number 46. Current market price: $0.60, TCGplayer market prices via Scryfall.
Other Goblin creatures you control attack each combat if able. At the beginning of combat on your turn, create a 1/1 red Goblin creature token with haste. Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Goblin.