The Meathook Massacre

When The Meathook Massacre enters, each creature gets -X/-X until end of turn.
Whenever a creature you control dies, each opponent loses 1 life.
Whenever a creature an opponent controls dies, you gain 1 life.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Alhammarret's Archive

If you would gain life, you gain twice that much life instead.
If you would draw a card except the first one you draw in each of your draw steps, draw two cards instead.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Verrak, Warped Sengir

Flying, deathtouch, lifelink
Whenever you activate an ability that isn't a mana ability, if life was paid to activate it, you may pay that much life again. If you do, copy that ability. You may choose new targets for the copy.

Teferi's Ageless Insight

If you would draw a card except the first one you draw in each of your draw steps, draw two cards instead.

Pull from Tomorrow

Strionic Resonator

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

Anointed Procession

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

March of the Canonized

When March of the Canonized enters, create X 1/1 white Vampire creature tokens with lifelink.
At the beginning of your upkeep, if your devotion to white and black is seven or greater, create a 4/3 white and black Vampire Demon creature token with flying.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Cruel Celebrant

Whenever Cruel Celebrant or another creature or planeswalker you control dies, each opponent loses 1 life and you gain 1 life.

Peer into the Abyss

Target player draws cards equal to half the number of cards in their library and loses half their life. Round up each time.

Sol Ring

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Elenda and Azor

Flying, ward {2}
Whenever Elenda and Azor attacks, you may pay {X}{W}{U}{B}. If you do, draw X cards.
At the beginning of each end step, you may pay 4 life. If you do, create a number of 1/1 black Vampire Knight creature tokens with lifelink equal to the number of cards you've drawn this turn.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")