Ikoria: Lair of Behemoths

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

Slitherwisp | Creature | Elemental Nightmare | Flash Whenever you cast another spell that has flash, you draw a card and each opponent loses 1 life. | Yigit Koroglu

Gyruda, Doom of Depths | Legendary Creature | Demon Kraken | Companion — Your starting deck contains only cards with even mana values. (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 Gyruda enters the battlefield, each player mills four cards. Put a creature card with an even mana value from among the milled cards onto the battlefield under your control. | Tyler Jacobson

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

Emergent Ultimatum | Sorcery | | Search your library for up to three monocolored cards with different names and exile them. An opponent chooses one of those cards. Shuffle that card into your library. You may cast the other cards without paying their mana costs. Exile Emergent Ultimatum. | Zack Stella

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

Zagoth Triome | Land | Swamp Forest Island | ({T}: Add {B}, {G}, or {U}.) Zagoth Triome enters the battlefield tapped. Cycling {3} ({3}, Discard this card: Draw a card.) | Eytan Zana