Dreadwaters

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

Shriekgeist

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

Drowner Initiate

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

Tome Scour

Psychic Strike

Counter target spell. Its controller mills two cards.

Thought Scour

Target player mills two cards.
Draw a card.

Dampen Thought

Target player mills four cards.
Splice onto Arcane {1}{U} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

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.

Griptide

Put target creature on top of its owner's library.

Broken Ambitions

Counter target spell unless its controller pays {X}. Clash with an opponent. If you win, that spell's controller mills four cards. (Each clashing player reveals the top card of their library, then puts that card on their choice of the top or bottom. A player wins if their card had a greater mana value.)

Homarid Explorer

When this creature enters, target player mills four cards.

Horrifying Revelation

Target player discards a card, then mills a card.

Deprive

As an additional cost to cast this spell, return a land you control to its owner's hand.
Counter target spell.

Pilfered Plans

Target player mills two cards. Draw two cards.

Returned Reveler

When this creature dies, each player mills three cards.

Curse of the Bloody Tome

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

Shriekhorn

This artifact enters with three charge counters on it.
{T}, Remove a charge counter from this artifact: Target player mills two cards.

Book Burning

Any player may have Book Burning deal 6 damage to them. If no one does, target player mills six cards.

Vision Charm

Choose one —
• Target player mills four cards.
• Choose a land type and a basic land type. Each land of the first chosen type becomes the second chosen type until end of turn.
• Target artifact phases out. (While it's phased out, it's treated as though it doesn't exist. It phases in before its controller untaps during their next untap step.)

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.)

Destroy the Evidence

Destroy target land. Its controller reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

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.

Jace's Erasure

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

Thought Collapse

Counter target spell. Its controller mills three cards.

Balustrade Spy

Flying
When this creature enters, target player reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Sage's Row Denizen

Whenever another blue creature you control enters, target player mills two cards.

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.)

Island

Mind Sculpt

Thassa's Bounty

Draw three cards. Target player mills three cards.

Chilling Shade

Flying
{S}: This creature gets +1/+1 until end of turn. ({S} can be paid with one mana from a snow source.)

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.)

Selhoff Occultist

Whenever this creature or another creature dies, target player mills a card.

Countermand

Counter target spell. Its controller mills four cards.

Gelid Shackles

Enchant creature
Enchanted creature can't block, and its activated abilities can't be activated.
{S}: Enchanted creature gains defender until end of turn. ({S} can be paid with one mana from a snow source.)

Chronic Flooding

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

Merfolk Mesmerist

Compelling Argument

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

Brainstorm

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

Crosstown Courier

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

Swamp

Iceberg Cancrix

Whenever another snow permanent you control enters, you may have target player mill two cards.

Merrow Witsniper

When this creature enters, target player mills a card.

Memory Sluice

Target player mills four cards.
Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)

Winds of Rebuke

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