Search your library for a card, put it into your hand, then shuffle.
Flashback—{1}{B}, Discard a card, Sacrifice a creature.

Flying, menace
As Uninvited Vampire enters, choose a creature an opponent controls. Uninvited Vampire has defender as long as that creature is on the battlefield.

Target player sacrifices a creature or planeswalker. You may put a deathtouch counter on up to one target creature you control, then that player loses 1 life for each creature you control with deathtouch.

Deathtouch
{1}{VP}{VP}: Variegated Shade gets +2/+2 until end of turn.

Protection from deathtouch
{T}: Put a deathtouch counter on another target creature. Activate only as a sorcery.

As an additional cost to cast this spell, sacrifice a creature or Food.
Destroy target creature or planeswalker.

Lifelink
When Vibeseeker enters, scry 1.

Drop — When Viral Upstarts enters, if you didn't cast any creature spells during your last turn, draw a card and you lose 1 life.

Indulgence
Whenever you indulge, each opponent loses 2 life.

Target player discards two cards and loses 2 life. If this spell's flashback cost was paid, instead that player discards a card and loses 1 life.
Flashback {B}

Approval — When Warrant-Borne Cop enters, target player reveals X cards from their hand, where X is the number of colors among permanents you control. You choose one of them. That player discards that card.

Lifelink
When Weathered Blackguard enters, you may attach target Equipment you control to it.
Wander {2}{B}

{1}{B}: Search your library for a card named Whisper Squad, put it onto the battlefield tapped, then shuffle.

Whenever another creature dies, if it had one or more counters on it, you may put one of those counters on Wicked Steed.

When Widowed Maiden enters, return target creature card from your graveyard to your hand.
Spellcharge 3

Menace
Cybersoul {3}{B}

When Worshipped Diva enters, if a creature died this turn, create a 2/1 red Zombie creature token with menace.

Lifelink
When Wretched Sackman dies, create a 2/2 black Zombie creature token with “This creature can't block.”

Once each turn, when one or more cards leave your graveyard, you may have each opponent lose 1 life and you gain 1 life.
{2}{B}, Exile Writheling from your graveyard: Exile target card in a graveyard. You draw a card and you lose 1 life. Activate only as a sorcery.

Whenever your Champion attacks, Xarr's Mockery gains indestructible until end of turn.

At the beginning of combat on your turn, you may integrate another creature you control. If you don't, tap Xavvac, Corrupter Core.
Permanents you control with cards integrated onto them have lifelink and deathtouch.

Flash
{2}{B}, Discard Zyxthax Apex: Each opponent loses 3 life and you gain 3 life.
{6}{B}{B}: Return Zyxthax Apex from your graveyard to the battlefield tapped with a finality counter on it.

A God Divided deals 2 damage to each nonenchantment creature.
Creatures you control get +1/+0 until end of turn.
You may sacrifice a creature. If you do, A God Divided deals damage to any target equal to the sacrificed creature's power.

Absolver of Ashes enters with a trample, first strike, menace, and +1/+1 counter on it.
At the beginning of your upkeep, remove a counter from Absolver of Ashes. If you can't, sacrifice it.

Whenever you cast a spell, if mana from an artifact source was spent to cast it, you may copy that spell, and you may choose new targets for the copy. Do this only once each turn.