Terisian Mindbreaker

Whenever this creature attacks, defending player mills half their library, rounded up.
Unearth {1}{U}{U}{U} ({1}{U}{U}{U}: 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.)

Grindclock

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

Didn't Say Please

Counter target spell. Its controller mills three cards.

Fabricate

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Zellix, Sanity Flayer

Hive Mind — Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.
{1}, {T}: Target player mills three cards.
Choose a Background (You can have a Background as a second commander.)

Mindcrank

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

Wash Away

Cleave {1}{U}{U} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Counter target spell [that wasn't cast from its owner's hand].

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Sphinx's Tutelage

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.

Prismatic Vista

{T}, Pay 1 life, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield, then shuffle.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Millstone

Evolving Wilds

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

Mirrormade

You may have this enchantment enter as a copy of any artifact or enchantment on the battlefield.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Riddlekeeper

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

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.)

Ulamog, the Ceaseless Hunger

When you cast this spell, exile two target permanents.
Indestructible
Whenever Ulamog attacks, defending player exiles the top twenty cards of their library.

Teferi's Tutelage

When this enchantment 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.)

Fog Bank

Defender (This creature can't attack.)
Flying
Prevent all combat damage that would be dealt to and dealt by this creature.

Manic Scribe

When this creature 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.

Visions of Beyond

Draw a card. If a graveyard has twenty or more cards in it, draw three cards instead.

Maddening Cacophony

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

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.

Rhystic Study

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

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, this artifact deals 3 damage to you.
{T}: Add {C}{C}.

Misty Rainforest

{T}, Pay 1 life, Sacrifice this land: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Thought Collapse

Spark Double

You may have this creature enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

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.

Midnight Clock

{T}: Add {U}.
{2}{U}: Put an hour counter on this artifact.
At the beginning of each upkeep, put an hour counter on this artifact.
When the twelfth hour counter is put on this artifact, shuffle your hand and graveyard into your library, then draw seven cards. Exile this artifact.

Polluted Delta

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

Tasha's Hideous Laughter

Each opponent exiles cards from the top of their library until that player has exiled cards with total mana value 20 or greater.

Realmbreaker, the Invasion Tree

{2}, {T}: Target opponent mills three cards. Put a land card from their graveyard onto the battlefield tapped under your control. It gains "If this land would leave the battlefield, exile it instead of putting it anywhere else."
{10}, {T}, Sacrifice Realmbreaker: Search your library for any number of Praetor cards, put them onto the battlefield, then shuffle.

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.)

Overwhelmed Apprentice

When this creature 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.)

Academy Ruins

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

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.)

Thought Scour

Target player mills two cards.
Draw a card.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Sakashima of a Thousand Faces

You may have Sakashima enter as a copy of another creature you control, except it has Sakashima's other abilities.
The "legend rule" doesn't apply to permanents you control.
Partner (You can have two commanders if both have partner.)

Treasure Cruise

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

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Undead Alchemist

If a Zombie you control would deal combat damage to a player, instead that player mills that many cards.
Whenever a creature card is put into an opponent's graveyard from their library, exile that card and create a 2/2 black Zombie creature token.

Fabled Passage

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Jace's Archivist

{U}, {T}: Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Mesmeric Orb

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Fleet Swallower

Whenever this creature attacks, target player mills half their library, rounded up.

Mind Sculpt

Sands of Delirium

Flooded Strand

{T}, Pay 1 life, Sacrifice this land: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Court of Cunning

When this enchantment enters, you become the monarch.
At the beginning of your upkeep, any number of target players each mill two cards. If you're the monarch, each of those players mills ten cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards. (They put the top three cards of their library into their graveyard.)

Cut Your Losses

Casualty 2 (As you cast this spell, you may sacrifice a creature with power 2 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Target player mills half their library, rounded down.

Drowned Secrets

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

Propaganda

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

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

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.)

Psychic Corrosion

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

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Dreamborn Muse

At the beginning of each player's upkeep, that player mills X cards, where X is the number of cards in their hand.

Island

Psychic Spiral

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

Fractured Sanity

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

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Terramorphic Expanse

Sol Ring

Drown in Dreams

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Target player draws X cards.
• Target player mills twice X cards.

Persistent Nightmare

Skulk (This creature can't be blocked by creatures with greater power.)
When this creature deals combat damage to a player, return it to its owner's hand.

Startled Awake

Target opponent mills thirteen cards.
{3}{U}{U}: Put this card from your graveyard onto the battlefield transformed. Activate only as a sorcery.

Startled Awake // Persistent Nightmare

Jace's Erasure

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

Scalding Tarn

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

Nyx Lotus

Nyx Lotus enters tapped.
{T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Traumatize

Target player mills half their library, rounded down.

Imprisoned in the Moon

Enchant creature, land, or planeswalker
Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.