Ikoria: Lair of Behemoths

Cubwarden | Creature | Cat | Mutate {2}{W}{W} (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.) Lifelink Whenever this creature mutates, create two 1/1 white Cat creature tokens with lifelink. | Kekai Kotaki

Mythos of Snapdax | Sorcery | | Each player chooses an artifact, a creature, an enchantment, and a planeswalker from among the nonland permanents they control, then sacrifices the rest. If {B}{R} was spent to cast this spell, you choose the permanents for each player instead. | Seb McKinnon

Mythos of Illuna | Sorcery | | Create a token that's a copy of target permanent. If {R}{G} was spent to cast this spell, instead create a token that's a copy of that permanent, except the token has "When this permanent enters the battlefield, if it's a creature, it fights up to one target creature you don't control." | Seb McKinnon

Dirge Bat | Creature | Bat | Mutate {4}{B}{B} (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 Flying Whenever this creature mutates, destroy target creature or planeswalker an opponent controls. | Paul Scott Canavan

Extinction Event | Sorcery | | Choose odd or even. Exile each creature with mana value of the chosen quality. (Zero is even.) | Filip Burburan

Everquill Phoenix | Creature | Phoenix | Mutate {3}{R} (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, create a red artifact token named Feather with "{1}, Sacrifice Feather: Return target Phoenix card from your graveyard to the battlefield tapped." | Lie Setiawan

Mythos of Vadrok | Sorcery | | Mythos of Vadrok deals 5 damage divided as you choose among any number of target creatures and/or planeswalkers. If {W}{U} was spent to cast this spell, until your next turn, those permanents can't attack or block and their activated abilities can't be activated. | Seb McKinnon

Gemrazer | Creature | Beast | Mutate {1}{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.) Reach, trample Whenever this creature mutates, destroy target artifact or enchantment an opponent controls. | Svetlin Velinov

Mythos of Brokkos | Sorcery | | If {U}{B} was spent to cast this spell, search your library for a card, put that card into your graveyard, then shuffle. Return up to two permanent cards from your graveyard to your hand. | Seb McKinnon

Frondland Felidar | Creature | Cat Beast | Vigilance Creatures you control with vigilance have "{1}, {T}: Tap target creature." | Steve Prescott

Umori, the Collector | Legendary Creature | Ooze | Companion — Each nonland card in your starting deck shares a card type. (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.) As Umori, the Collector enters the battlefield, choose a card type. Spells you cast of the chosen type cost {1} less to cast. | Jehan Choo

Whirlwind of Thought | Enchantment | | Whenever you cast a noncreature spell, draw a card. | Bram Sels

Titans' Nest | Enchantment | | At the beginning of your upkeep, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.) Exile a card from your graveyard: Add {C}. Spend this mana only to cast a spell that's one or more colors without {X} in its mana cost. | Cliff Childs

Song of Creation | Enchantment | | You may play an additional land on each of your turns. Whenever you cast a spell, draw two cards. At the beginning of your end step, discard your hand. | Noah Bradley