Arcane Signet

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

Nihilith

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Suspend 7—{1}{B} (Rather than cast this card from your hand, you may pay {1}{B} and exile it with seven time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)
Whenever a card is put into an opponent's graveyard from anywhere, if Nihilith is suspended, you may remove a time counter from Nihilith.

Clammy Prowler

Whenever Clammy Prowler attacks, another target attacking creature can't be blocked this turn.

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.

Psychic Symbiont

Flying
When Psychic Symbiont enters, target opponent discards a card and you draw a card.

Fractured Sanity

Each opponent mills fourteen cards.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)
When you cycle Fractured Sanity, each opponent mills four cards.

Mind Funeral

Target opponent reveals cards from the top of their library until four land cards are revealed. That player puts all cards revealed this way into their graveyard.

Roiling Horror

Roiling Horror's power and toughness are each equal to your life total minus the life total of an opponent with the most life.
Suspend X—{X}{B}{B}{B}. X can't be 0. (Rather than cast this card from your hand, you may pay {X}{B}{B}{B} and exile it with X time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)
Whenever a time counter is removed from Roiling Horror while it's exiled, target player loses 1 life and you gain 1 life.

Witch's Clinic

{T}: Add {C}.
{2}, {T}: Target commander gains lifelink until end of turn.

Scavenger Grounds

{T}: Add {C}.
{2}, {T}, Sacrifice a Desert: Exile all graveyards.

Mnemonic Betrayal

Exile all opponents' graveyards. You may cast spells from among those cards this turn, and mana of any type can be spent to cast them. At the beginning of the next end step, if any of those cards remain exiled, return them to their owners' graveyards.
Exile Mnemonic Betrayal.

Dimir Signet

Harsh Scrutiny

Target opponent reveals their hand. You choose a creature card from it. That player discards that card. Scry 1.

Despise

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

Devourer of Memory

Whenever one or more cards are put into your graveyard from your library, Devourer of Memory gets +1/+1 until end of turn and can't be blocked this turn.
{1}{U}{B}: Mill a card.

Heartless Conscription

Exile all creatures. For each card exiled this way, you may play that card for as long as it remains exiled, and mana of any type can be spent to cast that spell. Exile Heartless Conscription.

Halimar Depths

Halimar Depths enters tapped.
When Halimar Depths enters, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.

Takenuma, Abandoned Mire

{T}: Add {B}.
Channel — {3}{B}, Discard Takenuma, Abandoned Mire: Mill three cards, then return a creature or planeswalker card from your graveyard to your hand. This ability costs {1} less to activate for each legendary creature you control.

Geier Reach Sanitarium

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

Fear of Failed Tests

Whenever Fear of Failed Tests deals combat damage to a player, draw that many cards.

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Abyssal Gorestalker

When Abyssal Gorestalker enters, each player sacrifices two creatures of their choice.

Island

Summon Undead

You may mill three cards. Then return a creature card from your graveyard to the battlefield. (To mill a card, put the top card of your library into your graveyard.)

Bonders' Enclave

{T}: Add {C}.
{3}, {T}: Draw a card. Activate only if you control a creature with power 4 or greater.

Go Blank

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

Perplex

Counter target spell unless its controller discards their hand.
Transmute {1}{U}{B} ({1}{U}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Unmarked Grave

Search your library for a nonlegendary card, put that card into your graveyard, then shuffle.

Slum Reaper

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

Brainstealer Dragon

Flying
At the beginning of your end step, exile the top card of each opponent's library. You may play those cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.
Whenever a nonland permanent an opponent owns enters the battlefield under your control, they lose life equal to its mana value.

Cremate

Exile target card from a graveyard.
Draw a card.

Blood for Bones

As an additional cost to cast this spell, sacrifice a creature.
Return a creature card from your graveyard to the battlefield, then return another creature card from your graveyard to your hand.

Phyrexian Revoker

As Phyrexian Revoker enters, choose a nonland card name.
Activated abilities of sources with the chosen name can't be activated.

Dismal Backwater

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {B}.

Dinrova Horror

When Dinrova Horror enters, return target permanent to its owner's hand, then that player discards a card.

Mindleech Mass

Trample
Whenever Mindleech Mass deals combat damage to a player, you may look at that player's hand. If you do, you may cast a spell from among those cards without paying its mana cost.

Leyline of the Void

If Leyline of the Void is in your opening hand, you may begin the game with it on the battlefield.
If a card would be put into an opponent's graveyard from anywhere, exile it instead.

Crypt Lurker

When Crypt Lurker enters, you may sacrifice a creature or discard a creature card. If you do, draw a card.

Fear of Lost Teeth

When Fear of Lost Teeth dies, it deals 1 damage to any target and you gain 1 life.

Spoils of Blood

Create an X/X black Horror creature token, where X is the number of creatures that died this turn.

Zombify

Return target creature card from your graveyard to the battlefield.

Zellix, Sanity Flayer

Hive Mind — Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.
{1}, {T}: Target player mills three cards.
Choose a Background (You can have a Background as a second commander.)

Overlord of the Floodpits

Impending 4—{1}{U}{U} (If you cast this spell for its impending cost, it enters with four time counters and isn't a creature until the last is removed. At the beginning of your end step, remove a time counter from it.)
Flying
Whenever Overlord of the Floodpits enters or attacks, draw two cards, then discard a card.

Extract from Darkness

Each player mills two cards. Then you put a creature card from a graveyard onto the battlefield under your control.

Laboratory Brute

When Laboratory Brute enters, mill four cards.

Hunted Horror

Trample
When Hunted Horror enters, target opponent creates two 3/3 green Centaur creature tokens with protection from black.

Consuming Aberration

Consuming Aberration's power and toughness are each equal to the number of cards in your opponents' graveyards.
Whenever you cast a spell, each opponent reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Horror of the Dim

{U}: Horror of the Dim gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Damnation

Destroy all creatures. They can't be regenerated.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Grim Strider

Grim Strider gets -1/-1 for each card in your hand.

Infectious Horror

Whenever Infectious Horror attacks, each opponent loses 2 life.

Overcharged Amalgam

Flash
Flying
Exploit (When this creature enters, you may sacrifice a creature.)
When Overcharged Amalgam exploits a creature, counter target spell, activated ability, or triggered ability.

Tocasia's Dig Site

{T}: Add {C}.
{3}, {T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Crypt Incursion

Exile all creature cards from target player's graveyard. You gain 3 life for each card exiled this way.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Evolving Wilds

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

Swamp

Mind Grind

Each opponent reveals cards from the top of their library until they reveal X land cards, then puts all cards revealed this way into their graveyard. X can't be 0.

Psychic Corrosion

Whenever you draw a card, each opponent mills two cards.

Void Maw

Trample
If another creature would die, exile it instead.
Put a card exiled with Void Maw into its owner's graveyard: Void Maw gets +2/+2 until end of turn.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

Stinging Cave Crawler

Deathtouch
Descend 4 — Whenever Stinging Cave Crawler attacks, if there are four or more permanent cards in your graveyard, you draw a card and you lose 1 life.

Grazilaxx, Illithid Scholar

Whenever a creature you control becomes blocked, you may return it to its owner's hand.
Whenever one or more creatures you control deal combat damage to a player, draw a card.

Exhume

Each player puts a creature card from their graveyard onto the battlefield.

Thought Gorger

Trample
When Thought Gorger enters, put a +1/+1 counter on it for each card in your hand. If you do, discard your hand.
When Thought Gorger leaves the battlefield, draw a card for each +1/+1 counter on it.

Pit of Offerings

Pit of Offerings enters tapped.
When Pit of Offerings enters, exile up to three target cards from graveyards.
{T}: Add {C}.
{T}: Add one mana of any of the exiled cards' colors.

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.

Fear of Isolation

As an additional cost to cast this spell, return a permanent you control to its owner's hand.
Flying

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Umbris, Fear Manifest

Umbris, Fear Manifest gets +1/+1 for each card your opponents own in exile.
Whenever Umbris or another Nightmare or Horror you control enters, target opponent exiles cards from the top of their library until they exile a land card.

Spellskite

{U/P}: Change a target of target spell or ability to Spellskite. ({U/P} can be paid with either {U} or 2 life.)

Phantasmagorian

When you cast this spell, any player may discard three cards. If a player does, counter Phantasmagorian.
Discard three cards: Return Phantasmagorian from your graveyard to your hand.

Offer Immortality

Target creature gains deathtouch and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Ripples of Undeath

At the beginning of your first main phase, mill three cards. Then you may pay {1} and 3 life. If you do, put a card from among those cards into your hand.

Shizo, Death's Storehouse

{T}: Add {B}.
{B}, {T}: Target legendary creature gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Sign in Blood

Target player draws two cards and loses 2 life.

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Kindred Discovery

As Kindred Discovery enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Appendage Amalgam

Flash
Whenever Appendage Amalgam attacks, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Syphon Mind

Each other player discards a card. You draw a card for each card discarded this way.

Screaming Swarm

Flying
Whenever you attack with one or more creatures, target player mills that many cards. (To mill a card, a player puts the top card of their library into their graveyard.)
{2}{U}: Put Screaming Swarm from your graveyard into your library second from the top.

Hell's Caretaker

{T}, Sacrifice a creature: Return target creature card from your graveyard to the battlefield. Activate only during your upkeep.

Banehound

Silent Hallcreeper

Silent Hallcreeper can't be blocked.
Whenever Silent Hallcreeper deals combat damage to a player, choose one that hasn't been chosen —
• Put two +1/+1 counters on Silent Hallcreeper.
• Draw a card.
• Silent Hallcreeper becomes a copy of another target creature you control.

Blot Out

Target opponent exiles a creature or planeswalker they control with the greatest mana value among creatures and planeswalkers they control.

Castle Locthwain

Castle Locthwain enters tapped unless you control a Swamp.
{T}: Add {B}.
{1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.

Elder Brain

Menace
Whenever Elder Brain attacks a player, exile all cards from that player's hand, then they draw that many cards. You may play lands and cast spells from among the exiled cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.

Fear of Infinity

Flying, lifelink
Fear of Infinity can't block.
Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, you may return Fear of Infinity from your graveyard to your hand.

Forgotten Creation

Skulk (This creature can't be blocked by creatures with greater power.)
At the beginning of your upkeep, you may discard all the cards in your hand. If you do, draw that many cards.

Fear of Sleep Paralysis

Flying
Eerie — Whenever Fear of Sleep Paralysis or another enchantment you control enters and whenever you fully unlock a Room, tap up to one target creature and put a stun counter on it.
Stun counters can't be removed from permanents your opponents control. (They won't untap if they have stun counters.)

Praetor's Grasp

Search target opponent's library for a card and exile it face down. Then that player shuffles. You may play that card for as long as it remains exiled.

Yawgmoth's Vile Offering

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Put up to one target creature or planeswalker card from a graveyard onto the battlefield under your control. Destroy up to one target creature or planeswalker. Exile Yawgmoth's Vile Offering.

Wail of the Forgotten

Descend 8 — Choose one. If there are eight or more permanent cards in your graveyard as you cast this spell, choose one or more instead.
• Return target nonland permanent to its owner's hand.
• Target opponent discards a card.
• Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

Phyrexian Obliterator

Trample
Whenever a source deals damage to Phyrexian Obliterator, that source's controller sacrifices that many permanents of their choice.

Gloom Sower

Whenever Gloom Sower becomes blocked by a creature, that creature's controller loses 2 life and you gain 2 life.

Command Tower

Faceless Butcher

When Faceless Butcher enters, exile another target creature.
When Faceless Butcher leaves the battlefield, return the exiled card to the battlefield under its owner's control.