Great Teacher's Decree is a uncommon Sorcery card from Dragons of Tarkir (DTK), collector number 21. Current market price: $0.18 (foil $0.30), TCGplayer market prices via Scryfall.
Creatures you control get +2/+1 until end of turn. Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)