Maddening Cacophony

Kicker {3}{U}
Each opponent mills eight cards. If this spell was kicked, instead each opponent mills half their library, rounded up.

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.

Sludge Monster

Whenever this creature enters or attacks, put a slime counter on up to one other target creature.
Non-Horror creatures with slime counters on them lose all abilities and have base power and toughness 2/2.

Extract from Darkness

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

Plague Spitter

At the beginning of your upkeep, this creature deals 1 damage to each creature and each player.
When this creature dies, it deals 1 damage to each creature and each player.

Rings of Brighthearth

Whenever you activate an ability, if it isn't a mana ability, you may pay {2}. If you do, copy that ability. You may choose new targets for the copy.

Cut Your Losses

Casualty 2 (As you cast this spell, you may sacrifice a creature with power 2 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Target player mills half their library, rounded down.

Dark Hatchling

Flying
When this creature enters, destroy target nonblack creature. It can't be regenerated.

River of Tears

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

Nephalia Drownyard

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

Fractured Sanity

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

Grell Philosopher

Aberrant Tinkering — When this creature enters and at the beginning of your upkeep, each Horror you control gains all activated abilities of target artifact an opponent controls until end of turn. You may spend blue mana as though it were mana of any color to activate those abilities.

Port of Karfell

This land enters tapped.
{T}: Add {U}.
{3}{U}{B}{B}, {T}, Sacrifice this land: Mill four cards, then return a creature card from your graveyard to the battlefield tapped. (To mill a card, put the top card of your library into your graveyard.)

Sunken Hollow

({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.

Psionic Ritual

Replicate—Tap an untapped Horror you control. (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)
Exile target instant or sorcery card from a graveyard and copy it. You may cast the copy without paying its mana cost.
Exile Psionic Ritual.

Chasm Skulker

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

Plant Tadpoles

Tap X target creatures. They don't untap during their controllers' next untap steps. (Then exile this card. You may cast the creature later from exile.)

Illithid Harvester

Ceremorphosis — When this creature enters, turn any number of target tapped nontoken creatures face down. They're 2/2 Horror creatures.

Illithid Harvester // Plant Tadpoles

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Aboleth Spawn

Flash
Ward {2}
Probing Telepathy — Whenever a creature entering 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.

Dream Fracture

Counter target spell. Its controller draws a card.
Draw a card.

Sewer Nemesis

As this creature enters, choose a player.
Sewer Nemesis's power and toughness are each equal to the number of cards in the chosen player's graveyard.
Whenever the chosen player casts a spell, that player mills a card.

Fellwar Stone

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

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Bojuka Bog

This land enters tapped.
When this land enters, 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.

In Garruk's Wake

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

Haunted One

Commander creatures you own have "Whenever this creature becomes tapped, it and other creatures you control that share a creature type with it each get +2/+0 and gain undying until end of turn." (When a creature with undying 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.)

Swamp

Evolving Wilds

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

Nemesis of Reason

Whenever this creature attacks, defending player mills ten cards.

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

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 this creature.

Eldritch Pact

Target player draws X cards and loses X life, where X is the number of cards in their graveyard.

Mind Flayer

Dominate Monster — When this creature enters, gain control of target creature for as long as you control this creature.

Command Tower

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

Path of Ancestry

This land enters 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.)

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Syphon Mind

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

Island

Watery Grave

({T}: Add {U} or {B}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Kindred Discovery

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

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.

Elder Brain

Menace
Whenever this creature 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.

Leyline of Anticipation

If this card is in your opening hand, you may begin the game with it on the battlefield.
You may cast spells as though they had flash.

Spellskite

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

Dross Harvester

Protection from white
At the beginning of your end step, you lose 4 life.
Whenever a creature dies, you gain 2 life.

Nighthowler

Bestow {2}{B}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
This creature and enchanted creature each get +X/+X, where X is the number of creature cards in all graveyards.

Arcane Signet

Temple of the False God

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

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Phyrexian Rager

When this creature enters, you draw a card and you lose 1 life.

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 this card to its owner's hand.

Stonespeaker Crystal

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Exile any number of target players' graveyards. Draw a card.

Hunted Horror

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

Reflections of Littjara

As this enchantment enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. This artifact deals 1 damage to you.

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.

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Overcharged Amalgam

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

Dimir Keyrune

{T}: Add {U} or {B}.
{U}{B}: This artifact becomes a 2/2 blue and black Horror artifact creature until end of turn and can't be blocked this turn.

Aqueous Form

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Umbris, Fear Manifest

Umbris 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.

Wharf Infiltrator

Skulk (This creature can't be blocked by creatures with greater power.)
Whenever this creature 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.

Phyrexian Revoker

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

Guiltfeeder

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Whenever this creature attacks and isn't blocked, defending player loses 1 life for each card in their graveyard.

Ravenous Chupacabra

When this creature enters, destroy target creature an opponent controls.

Dauthi Horror

Shadow (This creature can block or be blocked by only creatures with shadow.)
This creature can't be blocked by white creatures.

Herald's Horn

As this artifact enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Morphic Pool

This land enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Sol Ring

Crippling Fear

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

Black Market

Whenever a creature dies, put a charge counter on this enchantment.
At the beginning of your first main phase, add {B} for each charge counter on this enchantment.

Drown in the Loch

Choose one —
• Counter target spell with mana value less than or equal to the number of cards in its controller's graveyard.
• Destroy target creature with mana value less than or equal to the number of cards in its controller's graveyard.

Rogue's Passage

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

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 this card is suspended, you may remove a time counter from this card.

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.

Exotic Orchard

Memory Plunder

You may cast target instant or sorcery card from an opponent's graveyard without paying its mana cost.

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.)

Choked Estuary

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