Metallurgic Summonings is a mythic Enchantment card from Kaladesh Promos (PKLD), collector number 56s. Current market price: — (foil $8.62), TCGplayer market prices via Scryfall.
Whenever you cast an instant or sorcery spell, create an X/X colorless Construct artifact creature token, where X is that spell's mana value. {3}{U}{U}, Exile this enchantment: Return all instant and sorcery cards from your graveyard to your hand. Activate only if you control six or more artifacts.