Ikoria: Lair of Behemoths

Mythos of Nethroi | Instant | | Destroy target nonland permanent if it's a creature or if {G}{W} was spent to cast this spell. | Seb McKinnon

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

Death's Oasis | Enchantment | | Whenever a nontoken creature you control dies, mill two cards. Then return a creature card with lesser mana value than the creature that died from your graveyard to your hand. {1}, Sacrifice Death's Oasis: You gain life equal to the highest mana value among creatures you control. | Grzegorz Rutkowski

Eerie Ultimatum | Sorcery | | Return any number of permanent cards with different names from your graveyard to the battlefield. | Jason A. Engle

Nethroi, Apex of Death | Legendary Creature | Cat Nightmare Beast | Mutate {4}{G/W}{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.) Deathtouch, lifelink Whenever this creature mutates, return any number of target creature cards with total power 10 or less from your graveyard to the battlefield. | Slawomir Maniak

Indatha Crystal | Artifact | | {T}: Add {W}, {B}, or {G}. Cycling {2} ({2}, Discard this card: Draw a card.) | Raoul Vitale

Indatha Triome | Land | Plains Swamp Forest | ({T}: Add {W}, {B}, or {G}.) Indatha Triome enters the battlefield tapped. Cycling {3} ({3}, Discard this card: Draw a card.) | Noah Bradley