Extra Deck

The Extra Deck is a secondary deck belonging to each player (as opposed to their Main Deck) and is one of the places in which cards can be.

The Extra Deck is a collection of special cards denoted by the "Extra Deck" symbol, that have different card backs. It is public to its owner but secret to the opponent. Order is not relevant but usually kept. The number of cards in each Extra Deck is public for both players. Normally the Extra Deck is kept as a face-down pile of cards on the Extra Deck Zone on the battlefield, but if can be consulted by its owner at any time.

The Extra Deck can be seen as a "second hand", because during a Rift Summoning Event or through the Convoke Action, players might be allowed to access and play cards directly from their Extra Decks.

The concept is very similar to Yu-Gi-Oh!'s Extra Deck.