Rally the Horde is a rare Sorcery card from Saviors of Kamigawa (SOK), collector number 110. Current market price: $0.28 (foil $3.35), TCGplayer market prices via Scryfall.
Exile the top card of your library. Exile the top card of your library. Exile the top card of your library. If the last card exiled isn't a land card, repeat this process. Create a 1/1 red Warrior creature token for each nonland card exiled this way.