Extract Brain

Target opponent chooses X cards from their hand. Look at those cards. You may cast a spell from among them without paying its mana cost.

Have

Plains

Synod Sanctum

{2}, {T}: Exile target permanent you control.
{2}, Sacrifice this artifact: Return all cards exiled with this artifact to the battlefield under your control.

Mnemonic Sphere

{1}{U}, Sacrifice this artifact: Draw two cards.
Channel — {U}, Discard this card: Draw a card.

Despark

Exile target permanent with mana value 4 or greater.

Raffine's Tower

({T}: Add {W}, {U}, or {B}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Sunken Hollow

({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.

Agent of Treachery

When this creature enters, gain control of target permanent.
At the beginning of your end step, if you control three or more permanents you don't own, draw three cards.

Wayfarer's Bauble

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

Commander's Sphere

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

Aron, Benalia's Ruin

Menace (This creature can't be blocked except by two or more creatures.)
{W}{B}, {T}, Sacrifice another creature: Put a +1/+1 counter on each creature you control.

Elder Brain

Menace
Whenever this creature 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.

Shadowheart, Dark Justiciar

{1}{B}, {T}, Sacrifice another creature: Draw X cards, where X is that creature's power.
Choose a Background (You can have a Background as a second commander.)

Cloudshift

Exile target creature you control, then return that card to the battlefield under your control.

Baleful Strix

Flying, deathtouch
When this creature enters, draw a card.

Merieke Ri Berit

Merieke Ri Berit doesn't untap during your untap step.
{T}: Gain control of target creature for as long as you control Merieke Ri Berit. When Merieke Ri Berit leaves the battlefield or becomes untapped, destroy that creature. It can't be regenerated.

Command Tower

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

Reckoner's Bargain

As an additional cost to cast this spell, sacrifice an artifact or creature.
You gain life equal to the sacrificed permanent's mana value. Draw two cards.

Swamp

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

Sower of Temptation

Flying
When this creature enters, gain control of target creature for as long as this creature remains on the battlefield.

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Tempted by the Oriq

For each opponent, gain control of up to one target creature or planeswalker that player controls with mana value 3 or less.

Slaughter the Strong

Each player chooses any number of creatures they control with total power 4 or less, then sacrifices all other creatures they control.

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Orzhov Basilica

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {W}{B}.

Ashnod's Altar

Captain N'ghathrod

Horrors you control have menace.
Whenever a Horror you control deals combat damage to a player, that player mills that many cards.
At the beginning of your end step, choose target artifact or creature card in an opponent's graveyard that was put there from their library this turn. Put it onto the battlefield under your control.

Hostage Taker

When this creature enters, exile another target creature or artifact until this creature leaves the battlefield. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Gonti, Lord of Luxury

Deathtouch
When Gonti enters, look at the top four cards of target opponent's library, exile one of them face down, then put the rest on the bottom of that library in a random order. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Dimir Aqueduct

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Nihiloor

When Nihiloor enters, for each opponent, tap up to one untapped creature you control. When you do, gain control of target creature that player controls with power less than or equal to the tapped creature's power for as long as you control Nihiloor.
Whenever you attack with a creature an opponent owns, you gain 2 life and that player loses 2 life.

Obscura Storefront

When this land enters, 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.

Void Rend

This spell can't be countered.
Destroy target nonland permanent.

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Watery Grave

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

Arcane Sanctum

This land enters tapped.
{T}: Add {W}, {U}, or {B}.

Mind Control

Enchant creature
You control enchanted creature.

Corrupted Conscience

Enchant creature
You control enchanted creature.
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Reliquary Tower

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

Athreos, Shroud-Veiled

Indestructible
As long as your devotion to white and black is less than seven, Athreos isn't a creature.
At the beginning of your end step, put a coin counter on another target creature.
Whenever a creature with a coin counter on it dies or is put into exile, return that card to the battlefield under your control.

Brainstealer Dragon

Flying
At the beginning of your end step, exile the top card of each opponent's library. You may play those 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.
Whenever a nonland permanent an opponent owns enters the battlefield under your control, they lose life equal to its mana value.

Soulherder

Whenever a creature is exiled from the battlefield, put a +1/+1 counter on this creature.
At the beginning of your end step, you may exile another target creature you control, then return that card to the battlefield under its owner's control.

Azorius Chancery

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {W}{U}.

Siphon Insight

Look at the top two cards of target opponent's library. Exile one of them face down and put the other on the bottom of that library. You may play the exiled card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell.
Flashback {1}{U}{B}

Nightveil Specter

Flying
Whenever this creature deals combat damage to a player, that player exiles the top card of their library.
You may play lands and cast spells from among cards exiled with this creature.

Beguiler of Wills

{T}: Gain control of target creature with power less than or equal to the number of creatures you control.

Rod of Absorption

Whenever a player casts an instant or sorcery spell, exile it instead of putting it into a graveyard as it resolves.
{X}, {T}, Sacrifice this artifact: You may cast any number of spells from among cards exiled with this artifact with total mana value X or less without paying their mana costs.

Evolving Wilds

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

Rishadan Pawnshop

{2}, {T}: Shuffle target nontoken permanent you control into its owner's library.

Gisa, Glorious Resurrector

If a creature an opponent controls would die, exile it instead.
At the beginning of your upkeep, put all creature cards exiled with Gisa onto the battlefield under your control. They gain decayed. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)

Arcane Signet

Umbris, Fear Manifest

Umbris gets +1/+1 for each card your opponents own in exile.
Whenever Umbris or another Nightmare or Horror you control enters, target opponent exiles cards from the top of their library until they exile a land card.

Control Magic

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Chainer, Dementia Master

All Nightmares get +1/+1.
{B}{B}{B}, Pay 3 life: Put target creature card from a graveyard onto the battlefield under your control. That creature is black and is a Nightmare in addition to its other creature types.
When Chainer leaves the battlefield, exile all Nightmares.

Entrancing Melody

Gain control of target creature with mana value X.

Ink-Eyes, Servant of Oni

Ninjutsu {3}{B}{B} ({3}{B}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Ink-Eyes deals combat damage to a player, you may put target creature card from that player's graveyard onto the battlefield under your control.
{1}{B}: Regenerate Ink-Eyes.

Thief of Sanity

Flying
Whenever this creature deals combat damage to a player, look at the top three cards of that player's library, exile one of them face down, then put the rest into their graveyard. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Sol Ring

King Macar, the Gold-Cursed

Inspired — Whenever King Macar becomes untapped, you may exile target creature. If you do, create a Gold token. (It's an artifact with "Sacrifice this token: Add one mana of any color.")

Essence Capture

Counter target creature spell. Put a +1/+1 counter on up to one target creature you control.

Intellect Devourer

Devour Intellect — When this creature enters, each opponent exiles a card from their hand until this creature leaves the battlefield.
Body Thief — You may play lands and cast spells from among cards exiled with this creature. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.

Restoration Angel

Flash
Flying
When this creature enters, you may exile target non-Angel creature you control, then return that card to the battlefield under your control.

Blatant Thievery

For each opponent, gain control of target permanent that player controls.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Counterspell

Dimir Signet

Mind Flayer

Dominate Monster — When this creature enters, gain control of target creature for as long as you control this creature.

Prairie Stream

({T}: Add {W} or {U}.)
This land enters tapped unless you control two or more basic lands.

Elesh Norn, Mother of Machines

Vigilance
If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Permanents entering don't cause abilities of permanents your opponents control to trigger.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Debtors' Knell

({W/B} can be paid with either {W} or {B}.)
At the beginning of your upkeep, put target creature card from a graveyard onto the battlefield under your control.

Exotic Orchard

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

Blue Sun's Twilight

Gain control of target creature with mana value X or less. If X is 5 or more, create a token that's a copy of that creature.

Thieving Amalgam

At the beginning of each opponent's upkeep, you manifest the top card of that player's library. (Put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)
Whenever a creature you control but don't own dies, its owner loses 2 life and you gain 2 life.

Xanathar, Guild Kingpin

At the beginning of your upkeep, choose target opponent. Until end of turn, that player can't cast spells, you may look at the top card of their library any time, you may play the top card of their library, and you may spend mana as though it were mana of any color to cast spells this way.

Fracture

Destroy target artifact, enchantment, or planeswalker.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Island

High Market

{T}: Add {C}.
{T}, Sacrifice a creature: You gain 1 life.

Ashiok, Nightmare Muse

+1: Create a 2/3 blue and black Nightmare creature token with "Whenever this token attacks or blocks, each opponent exiles the top two cards of their library."
−3: Return target nonland permanent to its owner's hand, then that player exiles a card from their hand.
−7: You may cast up to three spells from among face-up cards your opponents own from exile without paying their mana costs.

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.