Braids's Frightful Return

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — You may sacrifice a creature. If you do, each opponent discards a card.
II — Return target creature card from your graveyard to your hand.
III — Target opponent may sacrifice a nonland, nontoken permanent of their choice. If they don't, they lose 2 life and you draw a card.

Bladebrand

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

Headless Specter

Flying
Hellbent — Whenever this creature deals combat damage to a player, if you have no cards in hand, that player discards a card at random.

Asylum Visitor

At the beginning of each player's upkeep, if that player has no cards in hand, you draw a card and you lose 1 life.
Madness {1}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Liliana's Steward

{T}, Sacrifice this creature: Target opponent discards a card. Activate only as a sorcery.

Aspect of Lamprey

Enchant creature you control
When this Aura enters, target opponent discards two cards.
Enchanted creature has lifelink.

Venomous Changeling

Changeling (This card is every creature type.)
Deathtouch

Bog Witch

The Raven Man

At the beginning of each end step, if a player discarded a card this turn, create a 1/1 black Bird creature token with flying and "This token can't block."
{3}{B}, {T}: Each opponent discards a card. Activate only as a sorcery.

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Persistent Specimen

{2}{B}: Return this card from your graveyard to the battlefield tapped.

Macabre Waltz

Return up to two target creature cards from your graveyard to your hand, then discard a card.

Ichor Rats

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When this creature enters, each player gets a poison counter.

Memory Theft

Target opponent reveals their hand. You choose a nonland card from it. That player discards that card. You may put a card that has an Adventure that player owns from exile into that player's graveyard.

Noxious Toad

When this creature dies, each opponent discards a card.

Arms of Hadar

Creatures target player controls get -2/-2 until end of turn.

Ichor Explosion

As an additional cost to cast this spell, sacrifice a creature.
All creatures get -X/-X until end of turn, where X is the sacrificed creature's power.

Crippling Fear

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

Pilfer

Target opponent reveals their hand. You choose a nonland card from it. That player discards that card.

Deadbridge Shaman

When this creature dies, target opponent discards a card.

Merciless Executioner

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

From Under the Floorboards

Madness {X}{B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
Create three tapped 2/2 black Zombie creature tokens and you gain 3 life. If this spell's madness cost was paid, instead create X of those tokens and you gain X life.

Phyrexian Vivisector

Whenever a creature you control dies, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Cavern Whisperer

Mutate {3}{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.)
Menace (This creature can't be blocked except by two or more creatures.)
Whenever this creature mutates, each opponent discards a card.

Bloodsoaked Altar

{T}, Pay 2 life, Discard a card, Sacrifice a creature: Create a 5/5 black Demon creature token with flying. Activate only as a sorcery.

Sanitarium Skeleton

{2}{B}: Return this card from your graveyard to your hand.

Nezumi Bladeblesser

This creature has deathtouch as long as you control an artifact.
This creature has menace as long as you control an enchantment. (It can't be blocked except by two or more creatures.)

Mukotai Ambusher

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Lifelink