Perplex

Counter target spell unless its controller discards their hand.
Transmute {1}{U}{B} ({1}{U}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Academy Wall

Defender
Whenever you cast an instant or sorcery spell, you may draw a card. If you do, discard a card. This ability triggers only once each turn.

Thought Scour

Target player mills two cards.
Draw a card.

Chronic Flooding

Enchant land
Whenever enchanted land becomes tapped, its controller mills three cards.

Ghoulcaller's Bell

Winds of Rebuke

Return target nonland permanent to its owner's hand. Each player mills two cards.

Cathartic Adept

Dreadwaters

Target player mills X cards, where X is the number of lands you control.

Tome Scour

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Treasure Cruise

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Draw three cards.

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Tenured Oilcaster

Menace (This creature can't be blocked except by two or more creatures.)
Tenured Oilcaster gets +3/+0 as long as an opponent has eight or more cards in their graveyard.
Whenever Tenured Oilcaster attacks or blocks, each player mills a card.

Stream of Thought

Target player mills four cards. You shuffle up to four cards from your graveyard into your library.
Replicate {2}{U}{U} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)

Glacial Grasp

Tap target creature. Its controller mills two cards. That creature doesn't untap during its controller's next untap step. (They put the top two cards of their library into their graveyard.)
Draw a card.

Memory Lapse

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Paranoid Delusions

Target player mills three cards.
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.)

Grisly Spectacle

Destroy target nonartifact creature. Its controller mills cards equal to that creature's power.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Thriving Moor

Thriving Moor enters the battlefield tapped.
As Thriving Moor enters the battlefield, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Death's Approach

Enchant creature
Enchanted creature gets -X/-X, where X is the number of creature cards in its controller's graveyard.

Dark Ritual

Dimir Locket

{T}: Add {U} or {B}.
{U/B}{U/B}{U/B}{U/B}, {T}, Sacrifice Dimir Locket: Draw two cards.

Archaeomancer

When Archaeomancer enters the battlefield, return target instant or sorcery card from your graveyard to your hand.

Mind Stone

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

Behold the Multiverse

Scry 2, then draw two cards.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Curse of the Bloody Tome

Enchant player
At the beginning of enchanted player's upkeep, that player mills two cards.

Compelling Argument

Target player mills five cards.
Cycling {U} ({U}, Discard this card: Draw a card.)

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Swamp

Towering-Wave Mystic

Whenever Towering-Wave Mystic deals damage, target player mills that many cards.

Black Dragon Gate

Black Dragon Gate enters the battlefield tapped.
As Black Dragon Gate enters the battlefield, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Dimir Signet

Witness Protection

Enchant creature
Enchanted creature loses all abilities and is a green and white Citizen creature with base power and toughness 1/1 named Legitimate Businessperson. (It loses all other colors, card types, creature types, and names.)

Command Tower

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

Arcane Signet

Feed the Swarm

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

Thought Collapse

Counter target spell. Its controller mills three cards.

Dimir Cluestone

{T}: Add {U} or {B}.
{U}{B}, {T}, Sacrifice Dimir Cluestone: Draw a card.

Didn't Say Please

Dismal Backwater

Dismal Backwater enters the battlefield tapped.
When Dismal Backwater enters the battlefield, you gain 1 life.
{T}: Add {U} or {B}.

Ice Tunnel

({T}: Add {U} or {B}.)
Ice Tunnel enters the battlefield tapped.

Flood of Recollection

Return target instant or sorcery card from your graveyard to your hand. Exile Flood of Recollection.

Mortuary Mire

Mortuary Mire enters the battlefield tapped.
When Mortuary Mire enters the battlefield, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Drowner Initiate

Whenever a player casts a blue spell, you may pay {1}. If you do, target player mills two cards.

Wight of Precinct Six

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

Sage's Row Denizen

Whenever another blue creature enters the battlefield under your control, target player mills two cards.

Contaminated Aquifer

({T}: Add {U} or {B}.)
Contaminated Aquifer enters the battlefield tapped.

Stasis Field

Enchant creature
Enchanted creature has base power and toughness 0/2, has defender, and loses all other abilities.

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Thriving Isle

Thriving Isle enters the battlefield tapped.
As Thriving Isle enters the battlefield, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Venture Deeper

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

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Induce Paranoia

Counter target spell. If {B} was spent to cast this spell, that spell's controller mills X cards, where X is the spell's mana value.

Dimir Guildgate

Dimir Guildgate enters the battlefield tapped.
{T}: Add {U} or {B}.

Psychic Strike

Counter target spell. Its controller mills two cards.

Mindwrack Harpy

Flying
At the beginning of combat on your turn, each player mills three cards.

Island

Dream Twist

Target player mills three cards.
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Jace's Erasure

Whenever you draw a card, you may have target player mill a card.

Frogify

Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1. (It loses all other card types and creature types.)

Crypt Incursion

Exile all creature cards from target player's graveyard. You gain 3 life for each card exiled this way.

Mystic Sanctuary

({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.

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.

Obscura Storefront

When Obscura Storefront enters the battlefield, sacrifice it. When you do, search your library for a basic Plains, Island, or Swamp card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Ravenform

Exile target artifact or creature. Its controller creates a 1/1 blue Bird creature token with flying.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Nihil Spellbomb

{T}, Sacrifice Nihil Spellbomb: Exile target player's graveyard.
When Nihil Spellbomb is put into a graveyard from the battlefield, you may pay {B}. If you do, draw a card.

Meldweb Curator

When Meldweb Curator enters the battlefield, put up to one target instant or sorcery card from your graveyard on top of your library.

Charcoal Diamond

Charcoal Diamond enters the battlefield tapped.
{T}: Add {B}.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Jace's Phantasm

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

Shriekgeist

Flying
Whenever Shriekgeist deals combat damage to a player, that player mills two cards.

Sky Diamond

Sky Diamond enters the battlefield tapped.
{T}: Add {U}.

Vedalken Entrancer

Unseal the Necropolis

Each player mills three cards. Then you return up to two creature cards from your graveyard to your hand. (To mill three cards, a player puts the top three cards of their library into their graveyard.)

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Waterfront District

Waterfront District enters the battlefield tapped.
{T}: Add {U} or {B}.
{2}{U}{B}, {T}, Sacrifice Waterfront District: Draw a card.

Mind Sculpt

Mistvault Bridge

Mistvault Bridge enters the battlefield tapped.
Indestructible
{T}: Add {U} or {B}.