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

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

{1}, {T}: Add {U}{B}.

As Herald's Horn enters the battlefield, 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.

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

{T}: Add {C}. {1}, {T}, Sacrifice Mind Stone: Draw a card.

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

{T}: Add {C}{C}.

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

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

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.

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.

If an opponent would mill one or more cards, they mill twice that many cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

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.)

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.

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

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.

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.

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.

Aberrant Tinkering — When Grell Philosopher enters the battlefield 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.

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.

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

Dominate Monster — When Mind Flayer enters the battlefield, gain control of target creature for as long as you control Mind Flayer.

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

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.) Nighthowler and enchanted creature each get +X/+X, where X is the number of creature cards in all graveyards.

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

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

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

When Ravenous Chupacabra enters the battlefield, destroy target creature an opponent controls.

Landfall — Whenever a land enters the battlefield under your control, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

As Sewer Nemesis enters the battlefield, 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.

Whenever Sludge Monster enters the battlefield 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.

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

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent. {1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Whenever Terisian Mindbreaker attacks, defending player mills half their library, rounded up. Unearth {1}{U}{U}{U} ({1}{U}{U}{U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

At the beginning of each end step, put a slime counter on each creature you don't control. Creatures you don't control get -1/-1 for each slime counter on them. Whenever a creature you don't control with a slime counter on it dies, create a 1/1 black Slug creature token. {U}{B}, Sacrifice a Slug: Draw a card.

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.

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.

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.

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.)

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.

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.)

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

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Counter target spell.

Return target nonland permanent you don't control to its owner's hand. Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Counter target spell. Its controller mills three cards.

Choose one. If you control a commander as you cast this spell, you may choose both. • Target player draws X cards. • Target player mills twice X cards.

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.

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

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

As Cavern of Souls enters the battlefield, choose a creature type. {T}: Add {C}. {T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

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

{1}, {T}: Add {U}{B}.

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

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

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

({T}: Add {U}.)

Myriad Landscape enters the battlefield tapped. {T}: Add {C}. {2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

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

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.)

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

Shipwreck Marsh enters the battlefield tapped unless you control two or more other lands. {T}: Add {U} or {B}.

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

{T}: Add {C}. {U/B}, {T}: Add {U}{U}, {U}{B}, or {B}{B}.

({T}: Add {B}.)

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

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

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

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.

Destroy all creatures. They can't be regenerated.

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

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

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.

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

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.