Retether is a rare Sorcery card from Planar Chaos (PLC), collector number 13. Current market price: $18.03 (foil $70.85), TCGplayer market prices via Scryfall.
Return each Aura card from your graveyard to the battlefield. Only creatures can be enchanted this way. (Aura cards that can't enchant a creature on the battlefield remain in your graveyard.)