Overlay Regen 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, Overlay Regen is Unlimited.
YGOPRODeck lists Overlay Regen for these formats: Duel Links, Common Charity, Speed Duel, TCG, OCG, Master Duel.
A listed print of Overlay Regen appears in Amazing Defenders (AMDE-EN056) at Super Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Overlay Regen is about $0.08 on Cardmarket (prices change frequently).
