Ikoria: Lair of Behemoths

Essence Symbiote | Creature | Beast | Whenever a creature you control mutates, put a +1/+1 counter on that creature and you gain 2 life. | Jason Felix

Humble Naturalist | Creature | Human Druid | {T}: Add one mana of any color. Spend this mana only to cast a creature spell. | Matt Stewart

Kinnan, Bonder Prodigy | Legendary Creature | Human Druid | Whenever you tap a nonland permanent for mana, add one mana of any type that permanent produced. {5}{G}{U}: Look at the top five cards of your library. You may put a non-Human creature card from among them onto the battlefield. Put the rest on the bottom of your library in a random order. | Jason Rainville

Chevill, Bane of Monsters | Legendary Creature | Human Rogue | Deathtouch At the beginning of your upkeep, if your opponents control no permanents with bounty counters on them, put a bounty counter on target creature or planeswalker an opponent controls. Whenever a permanent an opponent controls with a bounty counter on it dies, you gain 3 life and draw a card. | Yongjae Choi

Skull Prophet | Creature | Human Druid | {T}: Add {B} or {G}. {T}: Mill two cards. | Nils Hamm

Fiend Artisan | Creature | Nightmare | Fiend Artisan gets +1/+1 for each creature card in your graveyard. {X}{B/G}, {T}, Sacrifice another creature: Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle. Activate only as a sorcery. | Yigit Koroglu