Sothera, the Supervoid

Whenever a creature you control dies, each opponent chooses a creature they control and exiles it.
At the beginning of your end step, if a player controls no creatures, sacrifice Sothera, then put a creature card exiled with it onto the battlefield under your control with two additional +1/+1 counters on it.

Kavaron Harrier

Whenever this creature attacks, you may pay {2}. If you do, create a 2/2 colorless Robot artifact creature token that's tapped and attacking. Sacrifice that token at end of combat.

Hullcarver

Depressurize

Target creature gets -3/-0 until end of turn. Then if that creature's power is 0 or less, destroy it.

Susurian Voidborn

Whenever this creature or another creature or artifact you control dies, target opponent loses 1 life and you gain 1 life.
Warp {B} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Elegy Acolyte

Lifelink
Whenever one or more creatures you control deal combat damage to a player, you draw a card and lose 1 life.
Void — At the beginning of your end step, if a nonland permanent left the battlefield this turn or a spell was warped this turn, create a 2/2 colorless Robot artifact creature token.

Swamp

Gravkill

Tragic Trajectory

Target creature gets -2/-2 until end of turn.
Void — That creature gets -10/-10 until end of turn instead if a nonland permanent left the battlefield this turn or a spell was warped this turn.

Insatiable Skittermaw

Menace (This creature can't be blocked except by two or more creatures.)
Void — At the beginning of your end step, if a nonland permanent left the battlefield this turn or a spell was warped this turn, put a +1/+1 counter on this creature.

Embrace Oblivion

As an additional cost to cast this spell, sacrifice an artifact or creature.
Destroy target creature or Spacecraft.

Lightless Evangel

Whenever you sacrifice another creature or artifact, put a +1/+1 counter on this creature.

Virus Beetle

When this creature enters, each opponent discards a card.

Melded Moxite

When this artifact enters, you may discard a card. If you do, draw two cards.
{3}, Sacrifice this artifact: Create a tapped 2/2 colorless Robot artifact creature token.

Comet Crawler

Lifelink
Whenever this creature attacks, you may sacrifice another creature or artifact. If you do, this creature gets +2/+0 until end of turn.

Geothermal Bog

({T}: Add {B} or {R}.)
This land enters tapped.

Plasma Bolt

Plasma Bolt deals 2 damage to any target.
Void — Plasma Bolt deals 3 damage instead if a nonland permanent left the battlefield this turn or a spell was warped this turn.

Cut Propulsion

Target creature deals damage to itself equal to its power. If that creature has flying, it deals twice that much damage to itself instead.

Mountain

Interceptor Mechan

Flying
When this creature enters, return target artifact or creature card from your graveyard to your hand.
Void — At the beginning of your end step, if a nonland permanent left the battlefield this turn or a spell was warped this turn, put a +1/+1 counter on this creature.

Xu-Ifit, Osteoharmonist

{T}: Return target creature card from your graveyard to the battlefield. It's a Skeleton in addition to its other types and has no abilities. Activate only as a sorcery.