If an opponent searched their library this turn, you may pay {0} rather than pay this spell's mana cost.

Target opponent mills thirteen cards.

Spells and abilities your opponents control can't cause their controller to search their library.

-1: Target player mills four cards. Then exile each opponent's graveyard.

+1: Create a 2/3 blue and black Nightmare creature token with "Whenever this creature attacks or blocks, each opponent exiles the top two cards of their library."

-3: Return target nonland permanent to its owner's hand, then that player exiles a card from their hand.

-7: You may cast up to three spells from among face-up cards your opponents own from exile without paying their mana costs.

+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.

Draw three cards, then put two cards from your hand on top of your library in any order.

As Choked Estuary enters the battlefield, you may reveal an Island or Swamp card from your hand. If you don't, Choked Estuary enters the battlefield tapped.

{T}: Add {U} or {B}.

Target player shuffles their graveyard into their library.

Draw a card.

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

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.

Counter target spell.

Counter target spell. Its controller mills three cards.

Dimir Aqueduct enters the battlefield tapped.

When Dimir Aqueduct enters the battlefield, return a land you control to its owner's hand.

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

Dimir Guildgate enters the battlefield tapped.

{T}: Add {U} or {B}.

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.

Drowned Catacomb enters the battlefield tapped unless you control an Island or a Swamp.

{T}: Add {U} or {B}.

Whenever you cast a blue spell, target player mills two cards.

{T}: Add {C}.

{U}{B}, {T}: Target player mills a card.

({T}: Add {U} or {B}.)

Fetid Pools enters the battlefield tapped.

Cycling {2} ({2}, Discard this card: Draw a card.)

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.

Target player mills ten cards.

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

Destroy target creature or planeswalker.

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

({T}: Add {U}.)

Counter target spell unless its controller pays {3}.

When Manic Scribe enters the battlefield, each opponent mills three cards.

Delirium -- At the beginning of each opponent's upkeep, if there are four or more card types among cards in your graveyard, that player mills three cards.

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

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.

Target opponent mills seven cards.

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

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.

({T}: Add {U}.)

Mystic Sanctuary enters the battlefield tapped unless you control three or more other Islands.

When Mystic Sanctuary enters the battlefield untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Counter target noncreature spell.

{T}: Add {C}.

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

When Overwhelmed Apprentice enters the battlefield, each opponent mills two cards. Then you scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

At the beginning of your upkeep, target opponent mills three cards, then you draw a card for each land card put into their graveyard this way.

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

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

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

Whenever a creature attacks you or a planeswalker you control, that creature's controller mills two cards.

Choose two target players. Each of them searches their library for a card, then shuffles and puts that card on top.

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.

Target opponent mills thirteen cards.

{3}{U}{U}: Put Startled Awake from your graveyard onto the battlefield transformed. Activate only as a sorcery.

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

When Persistent Nightmare deals combat damage to a player, return it to its owner's hand.

({T}: Add {U} or {B}.)

Sunken Hollow enters the battlefield tapped unless you control two or more basic lands.

({T}: Add {B}.)

({T}: Add {B}.)

({T}: Add {B}.)

Temple of Deceit enters the battlefield tapped.

When Temple of Deceit enters the battlefield, scry 1.

{T}: Add {U} or {B}.

Flying

Whenever Thief of Sanity deals combat damage to a player, look at the top three cards of that player's library, exile one of them face down, then put the rest into their graveyard. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast it.

Counter target spell. Its controller mills three cards.

Target player mills two cards.

Draw a card.

Target player mills half their library, rounded down.

{T}: Add {C}.

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

Defender

When Wall of Lost Thoughts enters the battlefield, target player mills four cards.

({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.