M'Odo, the Gnarled Oracle

Eminence — {X}, Discard a card: Target player reveals cards from the top of their library until they reveal a creature card with converted mana cost X or less. Put that card onto the battlefield under your control, then that player shuffles the rest into their library. Activate this ability only if M'Odo, the Gnarled Oracle is on the battlefield or in the command zone.

Grist, the Hunger Tide

As long as Grist, the Hunger Tide isn't on the battlefield, it's a 1/1 Insect creature in addition to its other types.
+1: Create a 1/1 black and green Insect creature token, then mill a card. If an Insect card was milled this way, put a loyalty counter on Grist and repeat this process.
−2: You may sacrifice a creature. When you do, destroy target creature or planeswalker.
−5: Each opponent loses life equal to the number of creature cards in your graveyard.