Nemesis of Reason

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

Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. Underground River deals 1 damage to you.

Mirko Vosk, Mind Drinker

Flying
Whenever Mirko Vosk, Mind Drinker deals combat damage to a player, that player reveals cards from the top of their library until they reveal four land cards, then puts those cards into their graveyard.

Freed from the Real

Enchant creature
{U}: Tap enchanted creature.
{U}: Untap enchanted creature.

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.

Sewer Nemesis

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.

Wight of Precinct Six

Wight of Precinct Six gets +1/+1 for each creature card in your opponents' graveyards.

Visions of Beyond

Draw a card. If a graveyard has twenty or more cards in it, draw three cards instead.

Mortivore

Mortivore's power and toughness are each equal to the number of creature cards in all graveyards.
{B}: Regenerate Mortivore.

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.

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.

Swamp

Hover Barrier

Mesmeric Orb

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Dimir Doppelganger

{1}{U}{B}: Exile target creature card from a graveyard. Dimir Doppelganger becomes a copy of that card, except it has this ability.

Silent Arbiter

No more than one creature can attack each combat.
No more than one creature can block each combat.

Eater of the Dead

{0}: If Eater of the Dead is tapped, exile target creature card from a graveyard and untap Eater of the Dead.

Havengul Lich

{1}: You may cast target creature card in a graveyard this turn. When you cast it this turn, Havengul Lich gains all activated abilities of that card until end of turn.

Exotic Orchard

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

Evil Twin

You may have Evil Twin enter the battlefield as a copy of any creature on the battlefield, except it has "{U}{B}, {T}: Destroy target creature with the same name as this creature."

Geth, Lord of the Vault

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
{X}{B}: Put target artifact or creature card with mana value X from an opponent's graveyard onto the battlefield under your control tapped. Then that player mills X cards.

Island

Dreamborn Muse

At the beginning of each player's upkeep, that player mills X cards, where X is the number of cards in their hand.

Wall of Frost

Defender
Whenever Wall of Frost blocks a creature, that creature doesn't untap during its controller's next untap step.

Jace, Memory Adept

+1: Draw a card. Target player mills a card.
0: Target player mills ten cards.
−7: Any number of target players each draw twenty cards.

Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters the battlefield, untap all creatures.

Phyrexian Metamorph

({U/P} can be paid with either {U} or 2 life.)
You may have Phyrexian Metamorph enter the battlefield as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types.

Keening Stone

{5}, {T}: Target player mills X cards, where X is the number of cards in that player's graveyard.

Darkwater Catacombs

Lazav, Dimir Mastermind

Hexproof
Whenever a creature card is put into an opponent's graveyard from anywhere, you may have Lazav, Dimir Mastermind become a copy of that card, except its name is Lazav, Dimir Mastermind, it's legendary in addition to its other types, and it has hexproof and this ability.

Lightning Greaves

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

Hedron Crab

Landfall — Whenever a land enters the battlefield under your control, target player mills three cards.

Endbringer

Untap Endbringer during each other player's untap step.
{T}: Endbringer deals 1 damage to any target.
{C}, {T}: Target creature can't attack or block this turn.
{C}{C}, {T}: Draw a card.

Phenax, God of Deception

Indestructible
As long as your devotion to blue and black is less than seven, Phenax isn't a creature.
Creatures you control have "{T}: Target player mills X cards, where X is this creature's toughness."

Jace's Phantasm

Flying
Jace's Phantasm gets +4/+4 as long as an opponent has ten or more cards in their graveyard.

Bonehoard

Living weapon (When this Equipment enters the battlefield, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +X/+X, where X is the number of creature cards in all graveyards.
Equip {2}

Psychic Corrosion

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

Dimir Signet

Pemmin's Aura

Enchant creature
{U}: Untap enchanted creature.
{U}: Enchanted creature gains flying until end of turn.
{U}: Enchanted creature gains shroud until end of turn. (It can't be the target of spells or abilities.)
{1}: Enchanted creature gets +1/-1 or -1/+1 until end of turn.

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.

Watery Grave

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

Junktroller

Defender
{T}: Put target card from a graveyard on the bottom of its owner's library.

Arcane Signet

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

Sol Ring

Lim-Dûl's Vault

Look at the top five cards of your library. As many times as you choose, you may pay 1 life, put those cards on the bottom of your library in any order, then look at the top five cards of your library. Then shuffle and put the last cards you looked at this way on top in any order.

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.

Disciple of Deceit

Inspired — Whenever Disciple of Deceit becomes untapped, you may discard a nonland card. If you do, search your library for a card with the same mana value as that card, reveal it, put it into your hand, then shuffle.

Dissipation Field

Whenever a permanent deals damage to you, return it to its owner's hand.

Thousand-Year Elixir

You may activate abilities of creatures you control as though those creatures had haste.
{1}, {T}: Untap target creature.

Sunken Hollow

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

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Tunnel Vision

Choose a card name. Target player reveals cards from the top of their library until a card with that name is revealed. If it is, that player puts the rest of the revealed cards into their graveyard and puts the card with the chosen name on top of their library. Otherwise, the player shuffles.

Phantasmal Image

You may have Phantasmal Image enter the battlefield as a copy of any creature on the battlefield, except it's an Illusion in addition to its other types and it has "When this creature becomes the target of a spell or ability, sacrifice it."

Sphinx's Tutelage

Whenever you draw a card, target opponent mills two cards. If two nonland cards that share a color were milled this way, repeat this process.
{5}{U}: Draw a card, then discard a card.

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.

Memory Erosion

Whenever an opponent casts a spell, that player mills two cards.

Command Tower

Memory Plunder

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

King Macar, the Gold-Cursed

Inspired — Whenever King Macar, the Gold-Cursed becomes untapped, you may exile target creature. If you do, create a Gold token. (It's an artifact with "Sacrifice this artifact: Add one mana of any color.")

Avatar of Woe

If there are ten or more creature cards total in all graveyards, this spell costs {6} less to cast.
Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{T}: Destroy target creature. It can't be regenerated.

Mindcrank

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

Duskmantle Guildmage

{1}{U}{B}: Whenever a card is put into an opponent's graveyard from anywhere this turn, that player loses 1 life.
{2}{U}{B}: Target player mills two cards.

Clever Impersonator

You may have Clever Impersonator enter the battlefield as a copy of any nonland permanent on the battlefield.

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Undead Alchemist

If a Zombie you control would deal combat damage to a player, instead that player mills that many cards.
Whenever a creature card is put into an opponent's graveyard from their library, exile that card and create a 2/2 black Zombie creature token.

Rhystic Study

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

Traumatize

Target player mills half their library, rounded down.

Tree of Perdition

Defender
{T}: Exchange target opponent's life total with Tree of Perdition's toughness.

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.

Drowned Catacomb

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

Jace's Archivist

{U}, {T}: Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.