A changer?

Psychosis Crawler

Psychosis Crawler's power and toughness are each equal to the number of cards in your hand.
Whenever you draw a card, each opponent loses 1 life.

Flayer of the Hatebound

Undying (When this creature 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.)
Whenever Flayer of the Hatebound or another creature enters from your graveyard, that creature deals damage equal to its power to any target.

Big Game Hunter

When Big Game Hunter enters, destroy target creature with power 4 or greater. It can't be regenerated.
Madness {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.)

Soul of Innistrad

Deathtouch
{3}{B}{B}: Return up to three target creature cards from your graveyard to your hand.
{3}{B}{B}, Exile Soul of Innistrad from your graveyard: Return up to three target creature cards from your graveyard to your hand.

Boneyard Parley

Exile up to five target creature cards from graveyards. An opponent separates those cards into two piles. Put all cards from the pile of your choice onto the battlefield under your control and the rest into their owners' graveyards.

Champion of Stray Souls

{3}{B}{B}, {T}, Sacrifice X other creatures: Return X target creature cards from your graveyard to the battlefield.
{5}{B}{B}: Put Champion of Stray Souls on top of your library from your graveyard.

Anje's Ravager

Anje's Ravager attacks each combat if able.
Whenever Anje's Ravager attacks, discard your hand, then draw three cards.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Ob Nixilis Reignited

+1: You draw a card and you lose 1 life.
−3: Destroy target creature.
−8: Target opponent gets an emblem with "Whenever a player draws a card, you lose 2 life."

Violent Eruption

Violent Eruption deals 4 damage divided as you choose among any number of targets.
Madness {1}{R}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Hazoret's Monument

Red creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, you may discard a card. If you do, draw a card.

Chainer, Nightmare Adept

Discard a card: You may cast a creature spell from your graveyard this turn. Activate only once each turn.
Whenever a nontoken creature you control enters, if you didn't cast it from your hand, it gains haste until your next turn.

Bloodhall Priest

Whenever Bloodhall Priest enters or attacks, if you have no cards in hand, Bloodhall Priest deals 2 damage to any target.
Madness {1}{B}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Grimoire of the Dead

{1}, {T}, Discard a card: Put a study counter on Grimoire of the Dead.
{T}, Remove three study counters from Grimoire of the Dead and sacrifice it: Put all creature cards from all graveyards onto the battlefield under your control. They're black Zombies in addition to their other colors and types.

Geth, Lord of the Vault

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
{X}{B}: Put target artifact or creature card with mana value X from an opponent's graveyard onto the battlefield under your control tapped. Then that player mills X cards.

Forgotten Cave

Forgotten Cave enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Key to the City

{T}, Discard a card: Up to one target creature can't be blocked this turn.
Whenever Key to the City becomes untapped, you may pay {2}. If you do, draw a card.

Necrogoyf

Necrogoyf's power is equal to the number of creature cards in all graveyards.
At the beginning of each player's upkeep, that player discards a card.
Madness {1}{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.)

Anje Falkenrath

Haste
{T}, Discard a card: Draw a card.
Whenever you discard a card, if it has madness, untap Anje Falkenrath.

Fiery Temper

Fiery Temper deals 3 damage to any target.
Madness {R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Murderous Compulsion

Destroy target tapped creature.
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.)

Hedonist's Trove

When Hedonist's Trove enters, exile target opponent's graveyard.
You may play lands from among cards exiled with Hedonist's Trove.
You may cast spells from among cards exiled with Hedonist's Trove. You can't cast more than one spell this way each turn.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

Rix Maadi, Dungeon Palace

{T}: Add {C}.
{1}{B}{R}, {T}: Each player discards a card. Activate only as a sorcery.

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Nightshade Assassin

First strike
When Nightshade Assassin enters, you may reveal X black cards in your hand. If you do, target creature gets -X/-X until end of turn.
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.)

Curse of Fool's Wisdom

Enchant player
Whenever enchanted player draws a card, they lose 2 life and you gain 2 life.
Madness {3}{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.)

Greven, Predator Captain

Menace
Greven, Predator Captain gets +X/+0, where X is the amount of life you've lost this turn.
Whenever Greven attacks, you may sacrifice another creature. If you do, you draw cards equal to that creature's power and you lose life equal to that creature's toughness.

Bloodfell Caves

Bloodfell Caves enters tapped.
When Bloodfell Caves enters, you gain 1 life.
{T}: Add {B} or {R}.

Stromkirk Occultist

Trample
Whenever Stromkirk Occultist deals combat damage to a player, exile the top card of your library. Until end of turn, you may play that card.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Reckless Wurm

Trample
Madness {2}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Akoum Refuge

Akoum Refuge enters tapped.
When Akoum Refuge enters, you gain 1 life.
{T}: Add {B} or {R}.

Beacon of Unrest

Put target artifact or creature card from a graveyard onto the battlefield under your control. Shuffle Beacon of Unrest into its owner's library.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Dark Withering

Destroy target nonblack creature.
Madness {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.)

Mountain

Zombie Infestation

Discard two cards: Create a 2/2 black Zombie creature token.

The Eldest Reborn

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each opponent sacrifices a creature or planeswalker of their choice.
II — Each opponent discards a card.
III — Put target creature or planeswalker card from a graveyard onto the battlefield under your control.

Blazing Rootwalla

{R}: Blazing Rootwalla gets +2/+0 until end of turn. Activate only once each turn.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Faith of the Devoted

Whenever you cycle or discard a card, you may pay {1}. If you do, each opponent loses 2 life and you gain 2 life.

Sanitarium Skeleton

{2}{B}: Return Sanitarium Skeleton from your graveyard to your hand.

Doomed Necromancer

{B}, {T}, Sacrifice Doomed Necromancer: Return target creature card from your graveyard to the battlefield.

Viashino Lashclaw

{T}, Discard a card: Creatures you control gain haste until end of turn.

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.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Malevolent Whispers

Gain control of target creature until end of turn. Untap that creature. It gets +2/+0 and gains haste until end of turn.
Madness {3}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Skyfire Phoenix

Flying, haste
When you cast your commander, return Skyfire Phoenix from your graveyard to the battlefield.

Solemn Simulacrum

When Solemn Simulacrum enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When Solemn Simulacrum dies, you may draw a card.

Rakdos Guildgate

Rakdos Guildgate enters tapped.
{T}: Add {B} or {R}.

Bone Miser

Whenever you discard a creature card, create a 2/2 black Zombie creature token.
Whenever you discard a land card, add {B}{B}.
Whenever you discard a noncreature, nonland card, draw a card.

Dying to Serve

Whenever you discard one or more cards, create a tapped 2/2 black Zombie creature token. This ability triggers only once each turn.

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.)

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Sanctum of Eternity

{T}: Add {C}.
{2}, {T}: Return target commander you own from the battlefield to your hand. Activate only during your turn.

Nightmare Unmaking

Choose one —
• Exile each creature with power greater than the number of cards in your hand.
• Exile each creature with power less than the number of cards in your hand.

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Hate Mirage

Choose up to two target creatures you don't control. For each of those creatures, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

Sol Ring

Command Tower

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

Overseer of the Damned

Flying
When Overseer of the Damned enters, you may destroy target creature.
Whenever a nontoken creature an opponent controls dies, create a tapped 2/2 black Zombie creature token.

Terminal Agony

Destroy target creature.
Madness {B}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Feast of Sanity

Whenever you discard a card, Feast of Sanity deals 1 damage to any target and you gain 1 life.

Cinder Barrens

Cinder Barrens enters tapped.
{T}: Add {B} or {R}.

Getting

Irencrag Pyromancer

Whenever you draw your second card each turn, Irencrag Pyromancer deals 3 damage to any target.

Squee, Goblin Nabob

At the beginning of your upkeep, you may return Squee, Goblin Nabob from your graveyard to your hand.

Barren Moor

Barren Moor enters tapped.
{T}: Add {B}.
Cycling {B} ({B}, Discard this card: Draw a card.)

Abolisher of Bloodlines

Flying
When this creature transforms into Abolisher of Bloodlines, target opponent sacrifices three creatures of their choice.

Voldaren Pariah

Flying
Sacrifice three other creatures: Transform Voldaren Pariah.
Madness {B}{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.)

Voldaren Pariah // Abolisher of Bloodlines

Shadowgrange Archfiend

When Shadowgrange Archfiend enters, each opponent sacrifices a creature with the greatest power among creatures they control. You gain life equal to the greatest power among creatures sacrificed this way.
Madness—{2}{B}, Pay 8 life. (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Magus of the Wheel

{1}{R}, {T}, Sacrifice Magus of the Wheel: Each player discards their hand, then draws seven cards.

Grave Scrabbler

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.)
When Grave Scrabbler enters, if its madness cost was paid, you may return target creature card from a graveyard to its owner's hand.

Avacyn's Judgment

Madness {X}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
Avacyn's Judgment deals 2 damage divided as you choose among any number of targets. If this spell's madness cost was paid, it deals X damage divided as you choose among those permanents and/or players instead.

Psychotic Haze

Psychotic Haze deals 1 damage to each creature and each player.
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.)

Wildfire Devils

When Wildfire Devils enters and at the beginning of your upkeep, choose a player at random. That player exiles an instant or sorcery card from their graveyard. Copy that card. You may cast the copy without paying its mana cost.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Bloodthirsty Blade

Equipped creature gets +2/+0 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
{1}: Attach Bloodthirsty Blade to target creature an opponent controls. Activate only as a sorcery.

Scaretiller

Whenever Scaretiller becomes tapped, choose one —
• You may put a land card from your hand onto the battlefield tapped.
• Return target land card from your graveyard to the battlefield tapped.

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Hedron Archive: Draw two cards.

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik, Son of Yawgmoth.

Archfiend of Spite

Flying
Whenever a source an opponent controls deals damage to Archfiend of Spite, that source's controller loses that much life unless they sacrifice that many permanents of their choice.
Madness {3}{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.)

Alchemist's Greeting

Alchemist's Greeting deals 4 damage to target creature.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Mortuary Mire

Mortuary Mire enters tapped.
When Mortuary Mire enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Swamp

Gorgon Recluse

Whenever Gorgon Recluse blocks or becomes blocked by a nonblack creature, destroy that creature at end of combat.
Madness {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.)

Call to the Netherworld

Return target black creature card from your graveyard to your hand.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Rakdos Carnarium

Rakdos Carnarium enters tapped.
When Rakdos Carnarium enters, return a land you control to its owner's hand.
{T}: Add {B}{R}.