Ikoria: Lair of Behemoths

Dreamtail Heron | Creature | Elemental Bird | Mutate {3}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.) Flying Whenever this creature mutates, draw a card. | Caio Monteiro

Frostveil Ambush | Instant | | Tap up to two target creatures. Those creatures don't untap during their controller's next untap step. Cycling {1} ({1}, Discard this card: Draw a card.) | Johan Grenier

Pouncing Shoreshark | Creature | Shark Beast | Mutate {3}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.) Flash Whenever this creature mutates, you may return target creature an opponent controls to its owner's hand. | Dan Scott

Voracious Greatshark | Creature | Shark | Flash When Voracious Greatshark enters the battlefield, counter target artifact or creature spell. | Mathias Kollros

Yorion, Sky Nomad | Legendary Creature | Bird Serpent | Companion — Your starting deck contains at least twenty cards more than the minimum deck size. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} any time you could cast a sorcery.) Flying When Yorion enters the battlefield, exile any number of other nonland permanents you own and control. Return those cards to the battlefield at the beginning of the next end step. | Steven Belledin

Keruga, the Macrosage | Legendary Creature | Dinosaur Hippo | Companion — Your starting deck contains only cards with mana value 3 or greater and land cards. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} any time you could cast a sorcery.) When Keruga, the Macrosage enters the battlefield, draw a card for each other permanent you control with mana value 3 or greater. | Dan Scott

Jegantha, the Wellspring | Legendary Creature | Elemental Elk | Companion — No card in your starting deck has more than one of the same mana symbol in its mana cost. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} any time you could cast a sorcery.) {T}: Add {W}{U}{B}{R}{G}. This mana can't be spent to pay generic mana costs. | Chris Rahn

Brokkos, Apex of Forever | Legendary Creature | Nightmare Beast Elemental | Mutate {2}{U/B}{G}{G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.) Trample You may cast Brokkos, Apex of Forever from your graveyard using its mutate ability. | Filip Burburan

Illuna, Apex of Wishes | Legendary Creature | Beast Elemental Dinosaur | Mutate {3}{R/G}{U}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.) Flying, trample Whenever this creature mutates, exile cards from the top of your library until you exile a nonland permanent card. Put that card onto the battlefield or into your hand. | Chris Rahn