Persistent Petitioners

{1}, {T}: Target player mills a card. (They put the top card of their library into their graveyard.)
Tap four untapped Advisors you control: Target player mills twelve cards.
A deck can have any number of cards named Persistent Petitioners.

Overwhelmed Apprentice

When Overwhelmed Apprentice enters, 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 and the rest on top in any order.)

Folio of Fancies

Players have no maximum hand size.
{X}{X}, {T}: Each player draws X cards.
{2}{U}, {T}: Each opponent mills cards equal to the number of cards in their hand.

Drowned Secrets

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

Riddlekeeper

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

Flood of Recollection

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

Navigator's Ruin

Raid — At the beginning of your end step, if you attacked this turn, target opponent mills four cards.

Sphinx Mindbreaker

Flying
When Sphinx Mindbreaker enters, each opponent mills ten cards.

Countermand

Counter target spell. Its controller mills four cards.

Ipnu Rivulet

{T}: Add {C}.
{T}, Pay 1 life: Add {U}.
{1}{U}, {T}, Sacrifice a Desert: Target player mills four cards.

Compelling Argument

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

Teferi's Tutelage

When Teferi's Tutelage enters, draw a card, then discard a card.
Whenever you draw a card, target opponent mills two cards. (They put the top two cards of their library into their graveyard.)

Predict

Choose a card name, then target player mills a card. If a card with the chosen name was milled this way, you draw two cards. Otherwise, you draw a card.

Brain Freeze

Target player mills three cards.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Archive Trap

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.

Dreadwaters

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

Grindclock

{T}: Put a charge counter on Grindclock.
{T}: Target player mills X cards, where X is the number of charge counters on Grindclock.

Grindstone

{3}, {T}: Target player mills two cards. If two cards that share a color were milled this way, repeat this process.

Jace, Wielder of Mysteries

If you would draw a card while your library has no cards in it, you win the game instead.
+1: Target player mills two cards. Draw a card.
−8: Draw seven cards. Then if your library has no cards in it, you win the game.

Sweet Oblivion

Target player mills four cards.
Escape—{3}{U}, Exile four other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Maddening Cacophony

Kicker {3}{U}
Each opponent mills eight cards. If this spell was kicked, instead each opponent mills half their library, rounded up.

Fractured Sanity

Each opponent mills fourteen cards.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)
When you cycle Fractured Sanity, each opponent mills four cards.

Voracious Reader

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Instant and sorcery spells you cast cost {1} less to cast.

Curious Homunculus

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell.
At the beginning of your upkeep, if there are three or more instant and/or sorcery cards in your graveyard, transform Curious Homunculus.

Curious Homunculus // Voracious Reader

Traumatize

Target player mills half their library, rounded down.

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.)

Bruvac the Grandiloquent

If an opponent would mill one or more cards, they mill twice that many cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Diligent Excavator

Whenever you cast a historic spell, target player mills two cards. (Artifacts, legendaries, and Sagas are historic.)

Memory Erosion

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

Psychic Spiral

Shuffle all cards from your graveyard into your library. Target player mills that many cards.

Jace Beleren

+2: Each player draws a card.
−1: Target player draws a card.
−10: Target player mills twenty cards.

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.

Manic Scribe

When Manic Scribe enters, 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.

Scavenger Grounds

{T}: Add {C}.
{2}, {T}, Sacrifice a Desert: Exile all graveyards.

Jace's Mindseeker

Flying
When Jace's Mindseeker enters, target opponent mills five cards. You may cast an instant or sorcery spell from among them without paying its mana cost.

Jace's Erasure

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

Relic of Progenitus

{T}: Target player exiles a card from their graveyard.
{1}, Exile Relic of Progenitus: Exile all graveyards. Draw a card.

Patient Rebuilding

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.

Fraying Sanity

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.

Deranged Assistant

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

Archaeomancer

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

Psychic Corrosion

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

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.)

Sentinel Totem

When Sentinel Totem enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}, Exile Sentinel Totem: Exile all graveyards.

Minister of Inquiries

When Minister of Inquiries enters, you get {E}{E} (two energy counters).
{T}, Pay {E}: Target player mills three cards.

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Sage's Row Denizen

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

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.

Wall of Lost Thoughts

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

Demilich

This spell costs {U} less to cast for each instant and sorcery spell you've cast this turn.
Whenever Demilich attacks, exile up to one target instant or sorcery card from your graveyard. Copy it. You may cast the copy.
You may cast Demilich from your graveyard by exiling four instant and/or sorcery cards from your graveyard in addition to paying its other costs.

Thought Collapse

Counter target spell. Its controller mills three cards.

Call to Mind

Return target instant or sorcery card from your graveyard to your hand.

Didn't Say Please

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

Vantress Gargoyle

Flying
Vantress Gargoyle can't attack unless defending player has seven or more cards in their graveyard.
Vantress Gargoyle can't block unless you have four or more cards in hand.
{T}: Each player mills a card.

Winds of Rebuke

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