March of the Machine: The Aftermath

Sarkhan, Soul Aflame | Legendary Creature | Human Shaman | Dragon spells you cast cost {1} less to cast. Whenever a Dragon enters the battlefield under your control, you may have Sarkhan, Soul Aflame become a copy of it until end of turn, except its name is Sarkhan, Soul Aflame and it's legendary in addition to its other types. | Eric Wilkerson

Kiora, Sovereign of the Deep | Legendary Creature | Merfolk Noble | Vigilance, ward {3} Whenever you cast a Kraken, Leviathan, Octopus, or Serpent spell from your hand, look at the top X cards of your library, where X is that spell's mana value. You may cast a spell with mana value less than X from among them without paying its mana cost. Put the rest on the bottom of your library in a random order. | Chris Rallis

Narset, Enlightened Exile | Legendary Creature | Human Monk | Creatures you control have prowess. Whenever Narset, Enlightened Exile attacks, exile target noncreature, nonland card with mana value less than Narset's power from a graveyard and copy it. You may cast the copy without paying its mana cost. | Marie Magny