Entropic Decay

Mill four cards. (Then exile this card. You may cast the creature later from exile.)

Gray Slaad

As long as there are four or more creature cards in your graveyard, this creature has menace and deathtouch.

Gray Slaad // Entropic Decay

Mind Raker

Devoid (This card has no color.)
When this creature enters, you may put a card an opponent owns from exile into that player's graveyard. If you do, each opponent discards a card.

Aven Heartstabber

Flying
As long as there are five or more mana values among cards in your graveyard, this creature gets +2/+2 and has deathtouch.
When this creature dies, mill two cards, then draw a card.

Millikin

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Ashiok, Sculptor of Fears

+2: Draw a card. Each player mills two cards.
−5: Put target creature card from a graveyard onto the battlefield under your control.
−11: Gain control of all creatures target opponent controls.

Dee Kay, Finder of the Lost

When Dee Kay enters, open an Attraction.
Whenever you roll a 2, each opponent loses 1 life and you gain 1 life.
Whenever you roll a 4, you may tap or untap target artifact or creature.
Whenever you roll a 6, return target creature card from your graveyard to your hand.

Archfiend of Sorrows

Flying
When this creature enters, creatures your opponents control get -2/-2 until end of turn.
Unearth {3}{B}{B} ({3}{B}{B}: 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.)

Araumi of the Dead Tide

{T}, Exile cards from your graveyard equal to the number of opponents you have: Target creature card in your graveyard gains encore until end of turn. The encore cost is equal to its mana cost. (Exile the creature card and pay its mana cost: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Fear of Death

Enchant creature
When this Aura enters, mill two cards. (Put the top two cards of your library into your graveyard.)
Enchanted creature gets -X/-0, where X is the number of cards in your graveyard.

Gloomfang Mauler

Swampcycling {2} ({2}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)
Backup 2 (When this creature enters, put two +1/+1 counters on target creature. If that's another creature, it gains the following ability until end of turn.)
Menace

Dreadwing Scavenger

Flying
Whenever this creature enters or attacks, draw a card, then discard a card.
Threshold — This creature gets +1/+1 and has deathtouch as long as there are seven or more cards in your graveyard.

Eternal Scourge

You may cast this card from exile.
When this creature becomes the target of a spell or ability an opponent controls, exile this creature.

Minamo, School at Water's Edge

{T}: Add {U}.
{U}, {T}: Untap target legendary permanent.

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.

Can't Wake Up

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Cruel Somnophage

Cruel Somnophage's power and toughness are each equal to the number of creature cards in all graveyards.

Cruel Somnophage // Can't Wake Up

Fear of the Dark

Whenever this creature attacks, if defending player controls no Glimmer creatures, it gains menace and deathtouch until end of turn. (A creature with menace can't be blocked except by two or more creatures.)

Fear of Falling

Flying
Whenever this creature attacks, target creature defending player controls gets -2/-0 and loses flying until your next turn.

Infuse

Untap target artifact, creature, or land.
Draw a card at the beginning of the next turn's upkeep.

Hidden Strings

You may tap or untap target permanent, then you may tap or untap another target permanent.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Magewright's Stone

{1}, {T}: Untap target creature that has an activated ability with {T} in its cost.

Fear of Failed Tests

Whenever this creature deals combat damage to a player, draw that many cards.

Cryptic Cruiser

Devoid (This card has no color.)
{2}{U}, Put a card an opponent owns from exile into that player's graveyard: Tap target creature.

Sigil of Myrkul

At the beginning of combat on your turn, mill a card. When you do, if there are four or more creature cards in your graveyard, put a +1/+1 counter on target creature you control and it gains deathtouch until end of turn. (To mill a card, put the top card of your library into your graveyard.)

Ulamog's Reclaimer

Devoid (This card has no color.)
When this creature enters, you may put a card an opponent owns from exile into that player's graveyard. If you do, return target instant or sorcery card from your graveyard to your hand.

Mindleech Mass

Trample
Whenever this creature deals combat damage to a player, you may look at that player's hand. If you do, you may cast a spell from among those cards without paying its mana cost.

Body Snatcher

When this creature enters, exile it unless you discard a creature card.
When this creature dies, exile it and return target creature card from your graveyard to the battlefield.

Trash Bin

Visit — Mill two cards, then return a card at random from your graveyard to your hand. (To mill a card, a player puts the top card of their library into their graveyard.)

Gloomlake Verge

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

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.

Sapphire Medallion

Blue spells you cast cost {1} less to cast.

Lazotep Convert

You may have this creature enter as a copy of any creature card in a graveyard, except it's a 4/4 black Zombie in addition to its other colors and types.

Invasion of Amonkhet

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When this Siege enters, each player mills three cards, then each opponent discards a card and you draw a card. (To mill three cards, a player puts the top three cards of their library into their graveyard.)

Invasion of Amonkhet // Lazotep Convert

Archmage's Newt

Whenever this creature deals combat damage to a player, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. That card gains flashback {0} until end of turn instead if this creature is saddled. (You may cast that card from your graveyard for its flashback cost. Then exile it.)
Saddle 3

Academy Ruins

{T}: Add {C}.
{1}{U}, {T}: Put target artifact card from your graveyard on top of your library.

Stormscape Familiar

Flying
White spells and black spells you cast cost {1} less to cast.

Deranged Assistant

Heed the Mists

Mill a card, then draw cards equal to the milled card's mana value.

Misthollow Griffin

Flying
You may cast this card from exile.

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.)

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.

Jet Medallion

Black spells you cast cost {1} less to cast.

Rhystic Study

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

Out of the Tombs

At the beginning of your upkeep, put two eon counters on this enchantment, then mill cards equal to the number of eon counters on it.
If you would draw a card while your library has no cards in it, instead return a creature card from your graveyard to the battlefield. If you can't, you lose the game.

Mire Triton

Deathtouch
When this creature enters, mill two cards and you gain 2 life. (To mill a card, put the top card of your library into your graveyard.)

Kiora, the Rising Tide

When Kiora enters, draw two cards, then discard two cards.
Threshold — Whenever Kiora attacks, if there are seven or more cards in your graveyard, you may create Scion of the Deep, a legendary 8/8 blue Octopus creature token.

Corridor Monitor

When this creature enters, untap target artifact or creature you control.

Iceberg Titan

Whenever this creature attacks, you may tap or untap target artifact or creature.

Inverted Iceberg

When this artifact enters, mill a card, then draw a card. (To mill a card, put the top card of your library into your graveyard.)
Craft with artifact {4}{U}{U} ({4}{U}{U}, Exile this artifact, Exile another artifact you control or an artifact card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)