Merciless Harlequin

Freerunning {1}{B} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
When this creature enters, you draw a card and you lose 1 life.

Mythos of Snapdax

Each player chooses an artifact, a creature, an enchantment, and a planeswalker from among the nonland permanents they control, then sacrifices the rest. If {B}{R} was spent to cast this spell, you choose the permanents for each player instead.

Blood Crypt

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

Kinbinding

Creatures you control get +X/+X, where X is the number of creatures that entered the battlefield under your control this turn.
At the beginning of combat on your turn, create a 1/1 green and white Kithkin creature token.

Nomad Outpost

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

Restart Sequence

Freerunning {1}{B} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Return target creature card from your graveyard to the battlefield.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Farewell

Choose one or more —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all graveyards.

Isshin, Two Heavens as One

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

Haunted Ridge

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

Command Tower

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

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Gathering Stone

As this artifact enters, choose a creature type.
Spells you cast of the chosen type cost {1} less to cast.
When this artifact enters and at the beginning of your upkeep, look at the top card of your library. If it's a card of the chosen type, you may reveal it and put it into your hand. If you don't put the card into your hand, you may put it into your graveyard.

Queen Marchesa

Deathtouch, haste
When Queen Marchesa enters, you become the monarch.
At the beginning of your upkeep, if an opponent is the monarch, create a 1/1 black Assassin creature token with deathtouch and haste.

Shattered Sanctum

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

Talisman of Indulgence

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

Seize the Day

Untap target creature. After this main phase, there is an additional combat phase followed by an additional main phase.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Undercity Eliminator

When this creature enters, you may sacrifice an artifact or creature. When you do, exile target creature an opponent controls.

Shadowy Backstreet

({T}: Add {W} or {B}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Shadow, Mysterious Assassin

Deathtouch
Throw — Whenever Shadow deals combat damage to a player, you may sacrifice another nonland permanent. If you do, draw two cards and each opponent loses life equal to the mana value of the sacrificed permanent.

Windcrag Siege

As this enchantment enters, choose Mardu or Jeskai.
• Mardu — If a creature attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
• Jeskai — At the beginning of your upkeep, create a 1/1 red Goblin creature token. It gains lifelink and haste until end of turn.

Clifftop Retreat

This land enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Savai Triome

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

Brotherhood Headquarters

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast an Assassin spell or a spell that has freerunning, or to activate an ability of an Assassin source.

Plains

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. This artifact deals 1 damage to you.

Ruinous Ultimatum

Destroy all nonland permanents your opponents control.

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Sundial of the Infinite

{1}, {T}: End the turn. Activate only during your turn. (Exile all spells and abilities from the stack. Discard down to your maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

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.")

Vault of Champions

This land enters tapped unless you have two or more opponents.
{T}: Add {W} or {B}.

Commander's Sphere

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

Unexpected Windfall

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

The Animus

At the beginning of your end step, exile up to one target legendary creature card from a graveyard with a memory counter on it.
{T}: Until your next turn, target legendary creature you control becomes a copy of target creature card in exile with a memory counter on it. Activate only as a sorcery.

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Swords to Plowshares

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

The Master, Multiplied

Myriad
The "legend rule" doesn't apply to creature tokens you control.
Triggered abilities you control can't cause you to sacrifice or exile creature tokens you control.

Swamp

Altaïr Ibn-La'Ahad

First strike
Whenever Altaïr attacks, exile up to one target Assassin creature card from your graveyard with a memory counter on it. Then for each creature card you own in exile with a memory counter on it, create a tapped and attacking token that's a copy of it. Exile those tokens at end of combat.

Neriv, Heart of the Storm

Flying
If a creature you control that entered this turn would deal damage, it deals twice that much damage instead.

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}

Grab the Prize

As an additional cost to cast this spell, discard a card.
Draw two cards. If the discarded card wasn't a land card, Grab the Prize deals 2 damage to each opponent.

Ruthless Lawbringer

When this creature enters, you may sacrifice another creature. When you do, destroy target nonland permanent.

Olivia, Opulent Outlaw

Flying, lifelink
Whenever one or more outlaws you control deal combat damage to a player, create a Treasure token. (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws.)
{3}, Sacrifice two Treasures: Put two +1/+1 counters on each creature you control. Activate only as a sorcery.

Sundown Pass

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

Corrupted Conviction

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

Caves of Koilos

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

Nekrataal

First strike
When this creature enters, destroy target nonartifact, nonblack creature. That creature can't be regenerated.

Elegant Parlor

({T}: Add {R} or {W}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Tormenting Voice

As an additional cost to cast this spell, discard a card.
Draw two cards.

Ashes of the Fallen

As this artifact enters, choose a creature type.
Each creature card in your graveyard has the chosen creature type in addition to its other types.

Thrilling Discovery

You gain 2 life. Then you may discard two cards. If you do, draw three cards.

Warleader's Call

Creatures you control get +1/+1.
Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Desmond Miles

Menace
Desmond Miles gets +1/+0 for each other Assassin you control and each Assassin card in your graveyard.
Whenever Desmond Miles deals combat damage to a player, surveil X, where X is the amount of damage it dealt to that player.

Terminate

Destroy target creature. It can't be regenerated.

Reno and Rude

Menace
Whenever Reno and Rude deals combat damage to a player, exile the top card of that player's library. Then you may sacrifice another creature or artifact. If you do, you may play the exiled card this turn, and mana of any type can be spent to cast it.

Vein Ripper

Flying
Ward—Sacrifice a creature.
Whenever a creature dies, target opponent loses 2 life and you gain 2 life.

Bloodline Pretender

Changeling (This card is every creature type.)
As this creature enters, choose a creature type.
Whenever another creature you control of the chosen type enters, put a +1/+1 counter on this creature.

Spectator Seating

This land enters tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

Raucous Theater

({T}: Add {B} or {R}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Changeling Wayfinder

Changeling (This card is every creature type.)
When this creature enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Arcane Signet

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. This land deals 1 damage to you.

Cathartic Reunion

As an additional cost to cast this spell, discard two cards.
Draw three cards.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Massacre Girl, Known Killer

Menace
Creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls dies, if its toughness was less than 1, draw a card.

Aya of Alexandria

Menace, lifelink
Whenever a historic creature you control deals combat damage to a player, create a 1/1 black Assassin creature token with menace. (Artifacts, legendaries, and Sagas are historic.)

Mari, the Killing Quill

Whenever a creature an opponent controls dies, exile it with a hit counter on it.
Assassins, Mercenaries, and Rogues you control have deathtouch and "Whenever this creature deals combat damage to a player, you may remove a hit counter from a card that player owns in exile. If you do, draw a card and create two Treasure tokens."

Roshan, Hidden Magister

Other creatures you control are Assassins in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
Face-down creatures you control have menace.
Whenever a permanent you control is turned face up, you draw a card and you lose 1 life.

Overpowering Attack

Freerunning {2}{R} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Untap all creatures you control that attacked this turn. If it's your main phase, there is an additional combat phase after this phase, followed by an additional main phase.

Mountain

Mithril Coat

Flash
Indestructible
When Mithril Coat enters, attach it to target legendary creature you control.
Equipped creature has indestructible.
Equip {3}

Generous Gift

Destroy target permanent. Its controller creates a 3/3 green Elephant creature token.

Godless Shrine

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

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Unstoppable Slasher

Deathtouch
Whenever this creature deals combat damage to a player, they lose half their life, rounded up.
When this creature dies, if it had no counters on it, return it to the battlefield tapped under its owner's control with two stun counters on it.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Isolated Chapel

This land enters tapped unless you control a Plains or a Swamp.
{T}: Add {W} or {B}.

Go for the Throat

Fell Mire

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.

Fell the Profane

Fell the Profane // Fell Mire

Entomb

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

Dolmen Gate

Prevent all combat damage that would be dealt to attacking creatures you control.

Massacre Girl

Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.

All-Fates Stalker

When this creature enters, exile up to one target non-Assassin creature until this creature leaves the battlefield.
Warp {1}{W} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Collective Inferno

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
As this enchantment enters, choose a creature type.
Double all damage that sources you control of the chosen type would deal.

Dragonskull Summit

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Sacred Foundry

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

Rising of the Day

Creatures you control have haste.
Legendary creatures you control get +1/+0.

Goblin Bombardment

Sacrifice a creature: This enchantment deals 1 damage to any target.

Luxury Suite

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