Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

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.

Morphic Pool

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

Spellskite

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

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Reanimate

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

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.

Drowned Catacomb

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

Watery Grave

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

Darkwater Catacombs

Lightning Greaves

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

Roaming Throne

Ward {2}
As Roaming Throne enters, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

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.

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Rogue's Passage

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

Grell Philosopher

Aberrant Tinkering — When Grell Philosopher 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.

Nemesis of Reason

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

Mindcrank

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

Shipwreck Marsh

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

Cavern of Souls

As Cavern of Souls enters, 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.

Sunken Hollow

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

Snow-Covered Swamp

Sunken Ruins

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

Psychic Corrosion

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

Murkwater Pathway

Clearwater Pathway

Clearwater Pathway // Murkwater Pathway

Herald's Horn

As Herald's Horn 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.

Memory Plunder

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

Thought Vessel

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

Bloodchief Ascension

At the beginning of each end step, if an opponent lost 2 or more life this turn, you may put a quest counter on Bloodchief Ascension. (Damage causes loss of life.)
Whenever a card is put into an opponent's graveyard from anywhere, if Bloodchief Ascension has three or more quest counters on it, you may have that player lose 2 life. If you do, you gain 2 life.

Cyclonic Rift

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.")

Exotic Orchard

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

Toxrill, the Corrosive

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.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Mind Flayer

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

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.

Reflections of Littjara

As Reflections of Littjara 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.)

Ruin Crab

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

Underground Sea

Prismatic Vista

{T}, Pay 1 life, Sacrifice Prismatic Vista: Search your library for a basic land card, put it onto the battlefield, then shuffle.

Imp's Mischief

Change the target of target spell with a single target. You lose life equal to that spell's mana value.

Talisman of Dominance

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

Nephalia Drownyard

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

Bruvac the Grandiloquent

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.)

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.

Dimir Signet

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.

Realmbreaker, the Invasion Tree

{2}, {T}: Target opponent mills three cards. Put a land card from their graveyard onto the battlefield tapped under your control. It gains "If this land would leave the battlefield, exile it instead of putting it anywhere else."
{10}, {T}, Sacrifice Realmbreaker, the Invasion Tree: Search your library for any number of Praetor cards, put them onto the battlefield, then shuffle.

Demonic Tutor

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

Leyline Axe

If this card is in your opening hand, you may begin the game with it on the battlefield.
Equipped creature gets +1/+1 and has double strike and trample.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Arcane Signet

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

Sewer Nemesis

As Sewer Nemesis 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.

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.

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.

Path of Ancestry

Path of Ancestry 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.)

Phyrexian Obliterator

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

Patchwork Banner

As Patchwork Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

Counterspell

Changeling Outcast

Changeling (This card is every creature type.)
Changeling Outcast can't block and can't be blocked.

Sludge Monster

Whenever Sludge Monster 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.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Fierce Guardianship

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

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.)

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.

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.

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.

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.

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.

Sol Ring

The Mindskinner

The Mindskinner can't be blocked.
If a source you control would deal damage to an opponent, prevent that damage and each opponent mills that many cards.

Command Tower

Deadly Rollick

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

Ancient Cellarspawn

Each spell you cast that's a Demon, Horror, or Nightmare costs {1} less to cast.
Whenever you cast a spell, if the amount of mana spent to cast it was less than its mana value, target opponent loses life equal to the difference.

Breach the Multiverse

Each player mills ten cards. For each player, choose a creature or planeswalker card in that player's graveyard. Put those cards onto the battlefield under your control. Then each creature you control becomes a Phyrexian in addition to its other types.

Dim Oubliette

When you unlock this door, mill three cards, then return a creature card from your graveyard to the battlefield.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Polluted Cistern

Whenever one or more cards are put into your graveyard from your library, each opponent loses 1 life for each card type among those cards.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Polluted Cistern // Dim Oubliette

Jace, the Perfected Mind

Compleated ({U/P} can be paid with {U} or 2 life. If life was paid, this planeswalker enters with two fewer loyalty counters.)
+1: Until your next turn, up to one target creature gets -3/-0.
−2: Target player mills three cards. Then if a graveyard has twenty or more cards in it, you draw three cards. Otherwise, you draw a card.
−X: Target player mills three times X cards.

Overlord of the Balemurk

Impending 5—{1}{B} (If you cast this spell for its impending cost, it enters with five 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.)
Whenever Overlord of the Balemurk enters or attacks, mill four cards, then you may return a non-Avatar creature card or a planeswalker card from your graveyard to your hand.

Snow-Covered Island

Undercity Sewers

({T}: Add {U} or {B}.)
Undercity Sewers enters tapped.
When Undercity Sewers enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Ravenous Chupacabra

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

Fraying Sanity

Enchant player
At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

Maddening Cacophony

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

Glimpse the Unthinkable

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.

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.

Guiltfeeder

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

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

Court of Cunning

When Court of Cunning enters, 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.)

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Hunted Horror

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

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.

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Tainted Isle

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

Drown in Dreams

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

Feed the Swarm

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

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Extract from Darkness

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