Sprout Swarm is a common Instant card from The List (PLST), collector number FUT-138. Current market price: $7.39, TCGplayer market prices via Scryfall.
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.) Create a 1/1 green Saproling creature token.