Archon of Cruelty

Flying
Whenever Archon of Cruelty enters or attacks, target opponent sacrifices a creature or planeswalker of their choice, discards a card, and loses 3 life. You draw a card and gain 3 life.

Phage the Untouchable

When Phage the Untouchable enters, if you didn't cast it from your hand, you lose the game.
Whenever Phage deals combat damage to a creature, destroy that creature. It can't be regenerated.
Whenever Phage deals combat damage to a player, that player loses the game.

Stitcher's Supplier

When Stitcher's Supplier enters or dies, mill three cards. (Put the top three cards of your library into your graveyard.)

Dermotaxi

Imprint — As Dermotaxi enters, exile a creature card from a graveyard.
Tap two untapped creatures you control: Until end of turn, Dermotaxi becomes a copy of the exiled card, except it's a Vehicle artifact in addition to its other types.

Persist

Return target nonlegendary creature card from your graveyard to the battlefield with a -1/-1 counter on it.

Torpor Orb

Creatures entering don't cause abilities to trigger.

Unmarked Grave

Search your library for a nonlegendary card, put that card into your graveyard, then shuffle.

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards.