Is Sprout Swarm legal in Standard, Modern, and Commander?

Sprout Swarm is legal in: Modern, Legacy, Vintage, Commander, Pauper.

What type of card is Sprout Swarm?

Sprout Swarm is an Instant. Its oracle text reads: "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."