Abyssal Persecutor

Flying, trample
You can't win the game and your opponents can't lose the game.

Life's Legacy

As an additional cost to cast this spell, sacrifice a creature.
Draw cards equal to the sacrificed creature's power.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Shadowheart, Dark Justiciar

{1}{B}, {T}, Sacrifice another creature: Draw X cards, where X is that creature's power.
Choose a Background (You can have a Background as a second commander.)

Relic Golem

This creature can't attack or block unless an opponent has eight or more cards in their graveyard.
{2}, {T}: Target player mills two cards. (They put the top two cards of their library into their graveyard.)

Traxos, Scourge of Kroog

Trample
Traxos enters tapped and doesn't untap during your untap step.
Whenever you cast a historic spell, untap Traxos. (Artifacts, legendaries, and Sagas are historic.)

Momentous Fall

As an additional cost to cast this spell, sacrifice a creature.
You draw cards equal to the sacrificed creature's power, then you gain life equal to its toughness.

Baloth Prime

This creature enters tapped with six stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you sacrifice a land, create a tapped 4/4 green Beast creature token and untap this creature.
{4}, Sacrifice a land: You gain 2 life.

Waning Wurm

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)

Kalakscion, Hunger Tyrant

Ravaging Riftwurm

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
If this creature was kicked, it enters with three additional time counters on it.

Daemogoth Titan

Whenever this creature attacks or blocks, sacrifice a creature.

The Gitrog, Ravenous Ride

Trample, haste
Whenever The Gitrog deals combat damage to a player, you may sacrifice a creature that saddled it this turn. If you do, draw X cards, then put up to X land cards from your hand onto the battlefield tapped, where X is the sacrificed creature's power.
Saddle 1

Pugnacious Hammerskull

Whenever this creature attacks while you don't control another Dinosaur, put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Lupine Prototype

This creature can't attack or block unless a player has no cards in hand.

Greater Good

Sacrifice a creature: Draw cards equal to the sacrificed creature's power, then discard three cards.