Otaria

The flashback grant is the whole point, and it is symmetric: while this plane is the one you're on, every instant and sorcery in every graveyard can be recast for its printed mana cost, then exiled. That turns the yard from a resource you build toward into a shared second hand, and it rewards whoever has been the most aggressive about spending spells rather than hoarding them. The static effect echoes the design of Snapcaster Mage and the flashback-matters decks of an earlier era, but stripped of any conditions: no discount, no rate to earn, just a blanket "cast it twice" applied to the entire table at once. The chaos clause is where the plane earns its Dominaria name, handing out an extra turn to whoever rolls the planar die into the chaos symbol, which is exactly the kind of swingy, run-the-table payoff planar magic was built to produce. The interaction between the two abilities is the design tension worth noting: an extra turn is far more dangerous when your graveyard is a fully loaded arsenal of replayable burn, draw, and removal, so the plane simultaneously fills the tank and hands someone the keys. It is a piece of the shared-canvas Planechase format, meaning its effect is not something you build around so much as something the whole game suddenly has to reckon with the moment it rolls into view.