Seal of the Ancients is a Normal Spell Card.
Spell Cards are usually activated from the hand on your turn unless their type gives another timing window.
On the current TCG and OCG Forbidden & Limited lists tracked here, Seal of the Ancients is Unlimited.
YGOPRODeck lists Seal of the Ancients for these formats: GOAT, OCG GOAT, Duel Links, Edison, TCG, OCG, Master Duel.
A listed print of Seal of the Ancients appears in Yu-Gi-Oh! Power of Chaos: Kaiba the Revenge promotional cards (PCK-003) at Prismatic Secret Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Seal of the Ancients is about $2.68 on Cardmarket (prices change frequently).
