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.")

Baleful Mastery

You may pay {1}{B} rather than pay this spell's mana cost.
If the {1}{B} cost was paid, an opponent draws a card.
Exile target creature or planeswalker.

Psychic Corrosion

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

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Jace's Erasure

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

Darkwater Catacombs

Mesmeric Orb

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

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.)

Morbid Opportunist

Whenever one or more other creatures die, draw a card. This ability triggers only once each turn.

Lazotep Convert

You may have this creature enter as a copy of any creature card in a graveyard, except it's a 4/4 black Zombie in addition to its other colors and types.

Invasion of Amonkhet

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When this Siege enters, each player mills three cards, then each opponent discards a card and you draw a card. (To mill three cards, a player puts the top three cards of their library into their graveyard.)

Invasion of Amonkhet // Lazotep Convert

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.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

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.)

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Nuclear Fallout

Each creature gets twice -X/-X until end of turn. Each player gets X rad counters.

River of Tears

{T}: Add {U}. If you played a land this turn, add {B} instead.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Swamp

Command Tower

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

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Visions of Beyond

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

Arcane Signet

Worry Beads

At the beginning of each player's upkeep, that player mills a card.

Dark Dabbling

Regenerate target creature. Draw a card. (The next time the creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, also regenerate each other creature you control.

Riverchurn Monument

{1}, {T}: Any number of target players each mill two cards. (Each of them puts the top two cards of their library into their graveyard.)
Exhaust — {2}{U}{U}, {T}: Any number of target players each mill cards equal to the number of cards in their graveyard. (Activate each exhaust ability only once.)

Dark Ritual

Counterspell

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Soul-Guide Lantern

When this artifact enters, exile target card from a graveyard.
{T}, Sacrifice this artifact: Exile each opponent's graveyard.
{1}, {T}, Sacrifice this artifact: 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.

Plumb the Forbidden

As an additional cost to cast this spell, you may sacrifice one or more creatures. When you do, copy this spell for each creature sacrificed this way.
You draw a card and you lose 1 life.

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.)

Shipwreck Marsh

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

Riddlekeeper

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

Irenicus's Vile Duplication

Create a token that's a copy of target creature you control, except the token has flying and it isn't legendary.

Nesting Grounds

{T}: Add {C}.
{1}, {T}: Move a counter from target permanent you control onto another target permanent. Activate only as a sorcery.

Mindcrank

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

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.)

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Sunken Hollow

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

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.)

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.

Island

Dimir Signet

Maddening Cacophony

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

Resculpt

Exile target artifact or creature. Its controller creates a 4/4 blue and red Elemental creature token.

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.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. This artifact deals 1 damage to you.

Drowned Catacomb

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

Selhoff Occultist

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

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.

Raul, Trouble Shooter

Once during each of your turns, you may cast a spell from among cards in your graveyard that were milled this turn.
{T}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Ghoulcaller's Bell

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Mystic Sanctuary

({T}: Add {U}.)
This land enters tapped unless you control three or more other Islands.
When this land enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Swan Song

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

Altar of the Brood

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

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.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

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, this creature becomes a copy of that card, except it has this ability.

Gloomlake Verge

{T}: Add {U}.
{T}: Add {B}. Activate only if you control an Island or a Swamp.

Scavenger Grounds

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

Withering Torment

Destroy target creature or enchantment. You lose 2 life.

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.)

Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. This land deals 1 damage to you.

Familiar's Ruse

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

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Spellskite

{U/P}: Change a target of target spell or ability to this creature. ({U/P} can be paid with either {U} or 2 life.)

Memory Erosion

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

Drowned Secrets

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

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.

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Haunted One

Commander creatures you own have "Whenever this creature becomes tapped, it and other creatures you control that share a creature type with it each get +2/+0 and gain undying until end of turn." (When a creature with undying dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Grindstone

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

March of Swirling Mist

As an additional cost to cast this spell, you may exile any number of blue cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Up to X target creatures phase out. (While they're phased out, they're treated as though they don't exist. Each one phases in before its controller untaps during their next untap step.)

Choked Estuary

As this land enters, you may reveal an Island or Swamp card from your hand. If you don't, this land enters tapped.
{T}: Add {U} or {B}.

Fellwar Stone

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

Corrupted Conviction

Propaganda

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