Undying Malice

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Rite of Oblivion

As an additional cost to cast this spell, sacrifice a nonland permanent.
Exile target nonland permanent.
Flashback {2}{W}{B} (You may cast this card from your graveyard for its flashback cost and any additional costs. Then exile it.)

Sol Ring

Vile Deacon

Whenever Vile Deacon attacks, it gets +X/+X until end of turn, where X is the number of Clerics on the battlefield.

Rot-Tide Gargantua

Exploit (When this creature enters, you may sacrifice a creature.)
When Rot-Tide Gargantua exploits a creature, each opponent sacrifices a creature of their choice.

Necropanther

Mutate {2}{W/B}{W/B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, return target creature card with mana value 3 or less from your graveyard to the battlefield.

Underworld Dreams

Whenever an opponent draws a card, Underworld Dreams deals 1 damage to that player.

Midnight Reaper

Whenever a nontoken creature you control dies, this creature deals 1 damage to you and you draw a card.

Fleshbag Marauder

When Fleshbag Marauder enters, each player sacrifices a creature of their choice.

Liesa, Forgotten Archangel

Flying, lifelink
Whenever another nontoken creature you control dies, return that card to its owner's hand at the beginning of the next end step.
If a creature an opponent controls would die, exile it instead.

Firja's Retribution

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 4/4 white Angel Warrior creature token with flying and vigilance.
II — Until end of turn, Angels you control gain "{T}: Destroy target creature with power less than this creature's power."
III — Angels you control gain double strike until end of turn.

Elderfang Disciple

When Elderfang Disciple enters, each opponent discards a card.

Go Blank

Target player discards two cards. Then exile that player's graveyard.

Fortuitous Find

Choose one or both —
• Return target artifact card from your graveyard to your hand.
• Return target creature card from your graveyard to your hand.

Soul Shatter

Each opponent sacrifices a creature or planeswalker with the highest mana value among creatures and planeswalkers they control.

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Fleshtaker

Whenever you sacrifice another creature, you gain 1 life and scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{1}, Sacrifice another creature: Fleshtaker gets +2/+2 until end of turn.

Unbreakable Bond

Return target creature card from your graveyard to the battlefield with a lifelink counter on it.

Demon of Loathing

Flying, trample
Whenever Demon of Loathing deals combat damage to a player, that player sacrifices a creature of their choice.

Touch of Moonglove

Target creature you control gets +1/+0 and gains deathtouch until end of turn. Whenever a creature dealt damage by that creature dies this turn, its controller loses 2 life. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it.)

Plumb the Forbidden

As an additional cost to cast this spell, you may sacrifice one or more creatures. When you do, copy this spell for each creature sacrificed this way.
You draw a card and you lose 1 life.

Bladebrand

Target creature gains deathtouch until end of turn.
Draw a card.

Lolth, Spider Queen

Whenever a creature you control dies, put a loyalty counter on Lolth, Spider Queen.
0: You draw a card and you lose 1 life.
−3: Create two 2/1 black Spider creature tokens with menace and reach.
−8: You get an emblem with "Whenever an opponent is dealt combat damage by one or more creatures you control, if that player lost less than 8 life this turn, they lose life equal to the difference."

Poison the Cup

Destroy target creature. If this spell was foretold, scry 2.
Foretell {1}{B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Undying Evil

Target creature gains undying until end of turn. (When it dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Drana's Emissary

Flying
At the beginning of your upkeep, each opponent loses 1 life and you gain 1 life.

Withercrown

Enchant creature
Enchanted creature has base power 0 and has "At the beginning of your upkeep, you lose 1 life unless you sacrifice this creature."