Dragon Mastery is a Continuous 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, Dragon Mastery is Unlimited.
YGOPRODeck lists Dragon Mastery for these formats: Duel Links, Common Charity, TCG, OCG, Master Duel.
Dragon Mastery belongs to the Dragunity archetype—use that tag when searching for engine pieces and tech options.
A listed print of Dragon Mastery appears in Dragunity Legion Structure Deck (SDDL-EN022) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Dragon Mastery is about $0.39 on Cardmarket (prices change frequently).
