Uchuulon

Uchuulon's power is equal to the number of Crabs, Oozes, and/or Horrors you control.
Horrific Symbiosis — At the beginning of your end step, exile up to one target creature card from an opponent's graveyard. If you do, create a token that's a copy of Uchuulon.

Ashiok, Nightmare Muse

+1: Create a 2/3 blue and black Nightmare creature token with "Whenever this creature attacks or blocks, each opponent exiles the top two cards of their library."
−3: Return target nonland permanent to its owner's hand, then that player exiles a card from their hand.
−7: You may cast up to three spells from among face-up cards your opponents own from exile without paying their mana costs.

Arvinox, the Mind Flail

Arvinox, the Mind Flail isn't a creature unless you control three or more permanents you don't own.
At the beginning of your end step, exile the bottom card of each opponent's library face down. For as long as those cards remain exiled, you may look at them, you may cast permanent spells from among them, and you may spend mana as though it were mana of any color to cast those spells.

Nemesis of Reason

Whenever Nemesis of Reason attacks, defending player mills ten cards.

Blot Out

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

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters the battlefield tapped unless you control two or more basic lands.

Dark Ritual

Vraska's Contempt

Exile target creature or planeswalker. You gain 2 life.

Swamp

Drowned Catacomb

Drowned Catacomb enters the battlefield tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

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.

Endless Evil

Enchant creature you control
At the beginning of your upkeep, create a token that's a copy of enchanted creature, except the token is 1/1.
When enchanted creature dies, if that creature was a Horror, return Endless Evil to its owner's hand.

Nautiloid Ship

Flying
When Nautiloid Ship enters the battlefield, exile target player's graveyard.
Whenever Nautiloid Ship deals combat damage to a player, you may put a creature card exiled with Nautiloid Ship onto the battlefield under your control.
Crew 3

See Double

This spell can't be copied.
Choose one. If an opponent has eight or more cards in their graveyard, you may choose both.
• Copy target spell. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)
• Create a token that's a copy of target creature.

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Phyrexian Rager

When Phyrexian Rager enters the battlefield, you draw a card and you lose 1 life.

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.

Dread Presence

Whenever a Swamp enters the battlefield under your control, choose one —
• You draw a card and you lose 1 life.
• Dread Presence deals 2 damage to any target and you gain 2 life.

Abyssal Gorestalker

When Abyssal Gorestalker enters the battlefield, each player sacrifices two creatures.

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.

Island

Temple of Deceit

Temple of Deceit enters the battlefield tapped.
When Temple of Deceit enters the battlefield, scry 1.
{T}: Add {U} or {B}.

Skaab Ruinator

As an additional cost to cast this spell, exile three creature cards from your graveyard.
Flying
You may cast Skaab Ruinator from your graveyard.

Dimir Signet

Sire of Stagnation

Devoid (This card has no color.)
Whenever a land enters the battlefield under an opponent's control, that player exiles the top two cards of their library and you draw two cards.

Dauthi Embrace

{B}{B}: Target creature gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)

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.

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.)

Nephalia Drownyard

{T}: Add {C}.
{1}{U}{B}, {T}: Target player mills three cards.

Phyrexian Obliterator

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

Imperious Mindbreaker

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.)
As long as Imperious Mindbreaker is paired with another creature, each of those creatures has "Whenever this creature attacks, each opponent mills cards equal to its toughness."

Falthis, Shadowcat Familiar

Commanders you control have menace and deathtouch.
Partner (You can have two commanders if both have partner.)

Fellwar Stone

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

King Narfi's Betrayal

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each player mills four cards. Then you may exile a creature or planeswalker card from each graveyard.
II, III — Until end of turn, you may cast spells from among cards exiled with King Narfi's Betrayal, and you may spend mana as though it were mana of any color to cast those spells.

Chainer, Dementia Master

All Nightmares get +1/+1.
{B}{B}{B}, Pay 3 life: Put target creature card from a graveyard onto the battlefield under your control. That creature is black and is a Nightmare in addition to its other creature types.
When Chainer, Dementia Master leaves the battlefield, exile all Nightmares.

River of Tears

{T}: Add {U}. If you played a land this turn, add {B} instead.

Sol Ring

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Ashiok, Nightmare Weaver

+2: Exile the top three cards of target opponent's library.
−X: Put a creature card with mana value X exiled with Ashiok, Nightmare Weaver onto the battlefield under your control. That creature is a Nightmare in addition to its other types.
−10: Exile all cards from all opponents' hands and graveyards.

Court of Cunning

When Court of Cunning enters the battlefield, you become the monarch.
At the beginning of your upkeep, any number of target players each mill two cards. If you're the monarch, each of those players mills ten cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Temple of Aclazotz

(Transforms from Arguel's Blood Fast.)
{T}: Add {B}.
{T}, Sacrifice a creature: You gain life equal to the sacrificed creature's toughness.

Arguel's Blood Fast

{1}{B}, Pay 2 life: Draw a card.
At the beginning of your upkeep, if you have 5 or less life, you may transform Arguel's Blood Fast.

Arguel's Blood Fast // Temple of Aclazotz

Dress Down

Flash
When Dress Down enters the battlefield, draw a card.
Creatures lose all abilities.
At the beginning of the end step, sacrifice Dress Down.

Crypt Incursion

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

Captain N'ghathrod

Horrors you control have menace.
Whenever a Horror you control deals combat damage to a player, that player mills that many cards.
At the beginning of your end step, choose target artifact or creature card in an opponent's graveyard that was put there from their library this turn. Put it onto the battlefield under your control.

Murkwater Pathway

Clearwater Pathway

Clearwater Pathway // Murkwater Pathway

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.

Toxic Deluge

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

Creeping Inn

Whenever Creeping Inn attacks, you may exile a creature card from your graveyard. If you do, each opponent loses X life and you gain X life, where X is the number of creature cards exiled with Creeping Inn.
{4}: Creeping Inn phases out.

Hostile Hostel

{T}: Add {C}.
{1}, {T}, Sacrifice a creature: Put a soul counter on Hostile Hostel. Then if there are three or more soul counters on it, remove those counters, transform it, then untap it. Activate only as a sorcery.

Hostile Hostel // Creeping Inn

Arcane Signet

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

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Command Tower

Defiler of Flesh

Menace
As an additional cost to cast black permanent spells, you may pay 2 life. Those spells cost {B} less to cast if you paid life this way. This effect reduces only the amount of black mana you pay.
Whenever you cast a black permanent spell, target creature you control gets +1/+1 and gains menace until end of turn.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. Talisman of Dominance deals 1 damage to you.

Grave Consequences

Each player may exile any number of cards from their graveyard. Then each player loses 1 life for each card in their graveyard.
Draw a card.

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.)

Wharf Infiltrator

Skulk (This creature can't be blocked by creatures with greater power.)
Whenever Wharf Infiltrator deals combat damage to a player, you may draw a card. If you do, discard a card.
Whenever you discard a creature card, you may pay {2}. If you do, create a 3/2 colorless Eldrazi Horror creature token.

Path of Ancestry

Path of Ancestry enters the battlefield tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Scavenger Grounds

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

Counterspell

Ashiok, Dream Render

Spells and abilities your opponents control can't cause their controller to search their library.
−1: Target player mills four cards. Then exile each opponent's graveyard.

Aboleth Spawn

Flash
Ward {2}
Probing Telepathy — Whenever a creature entering the battlefield under an opponent's control causes a triggered ability of that creature to trigger, you may copy that ability. You may choose new targets for the copy.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Choked Estuary

As Choked Estuary enters the battlefield, you may reveal an Island or Swamp card from your hand. If you don't, Choked Estuary enters the battlefield tapped.
{T}: Add {U} or {B}.

Temple of the False God

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

Slum Reaper

When Slum Reaper enters the battlefield, each player sacrifices a creature.

Psychic Symbiont

Flying
When Psychic Symbiont enters the battlefield, 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.

Umbris, Fear Manifest

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

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.

Dimir Aqueduct

Dimir Aqueduct enters the battlefield tapped.
When Dimir Aqueduct enters the battlefield, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Summary Dismissal

Exile all other spells and counter all abilities.

Nihil Spellbomb

{T}, Sacrifice Nihil Spellbomb: Exile target player's graveyard.
When Nihil Spellbomb is put into a graveyard from the battlefield, you may pay {B}. If you do, draw a card.

Essence Harvest

Target player loses X life and you gain X life, where X is the greatest power among creatures you control.

Ancient Craving

You draw three cards and you lose 3 life.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Aether Tunnel

Enchant creature
Enchanted creature gets +1/+0 and can't be blocked.

Bojuka Bog

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

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.

Relic of Progenitus

{T}: Target player exiles a card from their graveyard.
{1}, Exile Relic of Progenitus: Exile all graveyards. Draw a card.

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your precombat main phase, add {B} for each charge counter on Black Market.

Braids, Arisen Nightmare

At the beginning of your end step, you may sacrifice an artifact, creature, enchantment, land, or planeswalker. If you do, each opponent may sacrifice a permanent that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on Chasm Skulker.
When Chasm Skulker dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on Chasm Skulker. (They can't be blocked as long as defending player controls an Island.)

Barren Moor

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

Persistent Nightmare

Skulk (This creature can't be blocked by creatures with greater power.)
When Persistent Nightmare deals combat damage to a player, return it to its owner's hand.

Startled Awake

Target opponent mills thirteen cards.
{3}{U}{U}: Put Startled Awake from your graveyard onto the battlefield transformed. Activate only as a sorcery.

Startled Awake // Persistent Nightmare

Lonely Sandbar

Lonely Sandbar enters the battlefield tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Traitor's Clutch

Target creature gets +1/+0, becomes black, and gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)
Flashback {1}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

Spark Double

You may have Spark Double enter the battlefield as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Doom Whisperer

Flying, trample
Pay 2 life: Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Darkslick Shores

Darkslick Shores enters the battlefield tapped unless you control two or fewer other lands.
{T}: Add {U} or {B}.

Tasha's Hideous Laughter

Each opponent exiles cards from the top of their library until that player has exiled cards with total mana value 20 or more.

Rogue Class

(Gain the next level as a sorcery to add its ability.)
Whenever a creature you control deals combat damage to a player, exile the top card of that player's library face down. You may look at it for as long as it remains exiled.
{1}{U}{B}: Level 2
Creatures you control have menace.
{2}{U}{B}: Level 3
You may play cards exiled with Rogue Class, and you may spend mana as though it were mana of any color to cast those spells.