Terisian Mindbreaker

Whenever Terisian Mindbreaker 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.)

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.

Decanter of Endless Water

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

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Traumatize

Target player mills half their library, rounded down.

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.)

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.

Dimir Signet

Psychic Corrosion

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

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Shadowblood Ridge

Sheoldred, Whispering One

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
At the beginning of your upkeep, return target creature card from your graveyard to the battlefield.
At the beginning of each opponent's upkeep, that player sacrifices a creature of their choice.

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

The True Scriptures

(As this Saga enters and after your draw step, add a lore counter.)
I — For each opponent, destroy up to one target creature or planeswalker that player controls.
II — Each opponent discards three cards, then mills three cards.
III — Put all creature cards from all graveyards onto the battlefield under your control. Exile The True Scriptures, then return it to the battlefield (front face up).

Sheoldred

Menace
When Sheoldred enters, each opponent sacrifices a nontoken creature or planeswalker of their choice.
{4}{B}: Exile Sheoldred, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery and only if an opponent has eight or more cards in their graveyard.

Sheoldred // The True Scriptures

Kess, Dissident Mage

Flying
Once during each of your turns, you may cast an instant or sorcery spell from your graveyard. If a spell cast this way would be put into your graveyard, exile it instead.

Shipwreck Marsh

Shipwreck Marsh enters tapped unless you control two or more other lands.
{T}: Add {U} or {B}.

Command Tower

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

Consuming Aberration

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.

Darkwater Catacombs

Lord Xander, the Collector

When Lord Xander, the Collector enters, target opponent discards half the cards in their hand, rounded down.
Whenever Lord Xander attacks, defending player mills half their library, rounded down.
When Lord Xander dies, target opponent sacrifices half the nonland permanents they control of their choice, rounded down.

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 more.

Dark Ritual

Murkwater Pathway

Clearwater Pathway

Clearwater Pathway // Murkwater Pathway

Searstep Pathway

Blightstep Pathway

Blightstep Pathway // Searstep Pathway

Izzet Signet

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.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

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.

Phenax, God of Deception

Indestructible
As long as your devotion to blue and black is less than seven, Phenax isn't a creature.
Creatures you control have "{T}: Target player mills X cards, where X is this creature's toughness."

Bloodchief Ascension

At the beginning of each end step, if an opponent lost 2 or more life this turn, you may put a quest counter on Bloodchief Ascension. (Damage causes loss of life.)
Whenever a card is put into an opponent's graveyard from anywhere, if Bloodchief Ascension has three or more quest counters on it, you may have that player lose 2 life. If you do, you gain 2 life.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

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.)

Keening Stone

{5}, {T}: Target player mills X cards, where X is the number of cards in that player's graveyard.

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Didn't Say Please

Counter target spell. Its controller mills three cards.

Mind Grind

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.

Drown in the Loch

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.

Spark Double

You may have Spark Double 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.

Fake Your Own Death

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control and you create a Treasure token." (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Commander's Sphere

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

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.

Mirko Vosk, Mind Drinker

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.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

Dockside Extortionist

When Dockside Extortionist enters, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Yawgmoth's Will

Until end of turn, you may play lands and cast spells from your graveyard.
If a card would be put into your graveyard from anywhere this turn, exile that card instead.

Memory Erosion

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

Rise of the Dark Realms

Put all creature cards from all graveyards onto the battlefield under your control.

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.)

Mountain

Strionic Resonator

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Sanity Grinding

Chroma — Reveal the top ten cards of your library. For each blue mana symbol in the mana costs of the revealed cards, target opponent mills a card. Then put the cards you revealed this way on the bottom of your library in any order.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Sol Ring

Propaganda

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

Island

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Fabled Passage

{T}, Sacrifice Fabled Passage: 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.

Shadow Kin

Flash
At the beginning of your upkeep, each player mills three cards. You may exile a creature card from among the cards milled this way. If you do, Shadow Kin becomes a copy of that card, except it has this ability.

Training Center

Training Center enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Drowned Catacomb

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Xander's Lounge

({T}: Add {U}, {B}, or {R}.)
Xander's Lounge enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Arcane Signet

Reliquary Tower

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

Lavaglide Pathway

Riverglide Pathway

Riverglide Pathway // Lavaglide Pathway

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.

Rhystic Study

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

Morphic Pool

Morphic Pool enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Grim Tutor

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Tergrid's Lantern

{T}: Target player loses 3 life unless they sacrifice a nonland permanent of their choice or discard a card.
{3}{B}: Untap Tergrid's Lantern.

Tergrid, God of Fright

Menace
Whenever an opponent sacrifices a nontoken permanent or discards a permanent card, you may put that card from a graveyard onto the battlefield under your control.

Tergrid, God of Fright // Tergrid's Lantern

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Exotic Orchard

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

Sakashima of a Thousand Faces

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

Breach the Multiverse

Each player mills ten cards. For each player, choose a creature or planeswalker card in that player's graveyard. Put those cards onto the battlefield under your control. Then each creature you control becomes a Phyrexian in addition to its other types.

Haunted Ridge

Haunted Ridge enters tapped unless you control two or more other lands.
{T}: Add {B} or {R}.

Notion Thief

Flash
If an opponent would draw a card except the first one they draw in each of their draw steps, instead that player skips that draw and you draw a card.

Luxury Suite

Luxury Suite enters tapped unless you have two or more opponents.
{T}: Add {B} or {R}.

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

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.

Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Riddlekeeper

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

Supernatural Stamina

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control."

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.)

Mindcrank

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

Swamp

Stormcarved Coast

Stormcarved Coast enters tapped unless you control two or more other lands.
{T}: Add {U} or {R}.

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Maestros Theater

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

Elder Brain

Menace
Whenever Elder Brain attacks a player, exile all cards from that player's hand, then they draw that many cards. You may play lands and cast spells from among the exiled cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.

Crumbling Necropolis

Crumbling Necropolis enters tapped.
{T}: Add {U}, {B}, or {R}.

Maddening Cacophony

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