Arno Dorian

Deathtouch
Other Assassins you control get +2/+0.
Disguise {B}{R} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)

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.

Hookblade

When this Equipment enters, attach it to target creature you control.
Equipped creature gets +1/+0.
During your turn, equipped creature has flying.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Lightning Greaves

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

Caduceus, Staff of Hermes

Equipped creature has lifelink.
As long as you have 30 or more life, equipped creature gets +5/+5 and has indestructible and "Prevent all damage that would be dealt to this creature."
Equip {W}{W}

Brotherhood Patriarch

When this creature dies, each opponent loses 2 life and you gain 2 life.

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.

Plains

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.

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.

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.

Thrilling Discovery

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

Big Score

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.")

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.

Trailblazer's Boots

Equipped creature has nonbasic landwalk. (It can't be blocked as long as defending player controls a nonbasic land.)
Equip {2}

Reconstruct History

Return up to one target artifact card, up to one target enchantment card, up to one target instant card, up to one target sorcery card, and up to one target planeswalker card from your graveyard to your hand.
Exile Reconstruct History.

Haunted Ridge

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

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.")

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."

Royal Assassin

Hired Blade

Flash (You may cast this spell any time you could cast an instant.)

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Sacred Foundry

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

Swamp

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.

Ezio, Brash Novice

Whenever Ezio attacks, put a +1/+1 counter on it.
As long as Ezio has two or more counters on it, it has first strike and is an Assassin in addition to its other types.

Apple of Eden, Isu Relic

{T}, Pay 4 life, Sacrifice Apple of Eden: Look at target opponent's hand and exile those cards face down. You may play those cards this turn, and mana of any type can be spent to cast them. Until end of turn, whenever you play a land or cast a spell this way, its owner draws a card. At the beginning of the next end step, return the exiled cards to their owner's hand. Activate only as a sorcery.

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.)

Conspiracy

As this enchantment enters, choose a creature type.
Creatures you control are the chosen type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

The Revelations of Ezio

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Destroy target tapped creature an opponent controls.
II — Whenever an Assassin you control attacks this turn, put a +1/+1 counter on it.
III — Return target Assassin creature card from your graveyard to the battlefield with an additional +1/+1 counter on it.

Eivor, Battle-Ready

Vigilance (Attacking doesn't cause this creature to tap.)
Haste (This creature can attack as soon as it comes under your control.)
Whenever Eivor attacks, it deals damage equal to the number of Equipment you control to each opponent.

Bureau Headmaster

Equipment spells you cast cost {1} less to cast.
Equip abilities you activate cost {1} less to activate.

Brotherhood Regalia

Equipped creature has ward {2}, is an Assassin in addition to its other types, and can't be blocked.
Equip legendary creature {1}
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Poison-Blade Mentor

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever this creature attacks, another target Assassin you control gains deathtouch until end of turn.

Arcane Signet

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

Bleeding Effect

At the beginning of combat on your turn, creatures you control gain flying until end of turn if a creature card in your graveyard has flying. The same is true for first strike, double strike, deathtouch, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

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.

Dragonskull Summit

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

Vault of Champions

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

Petty Larceny

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.)
Look at the top two cards of target opponent's library and exile those cards face down. You may play those cards for as long as they remain exiled, and mana of any type can be spent to cast them. Create a Treasure token.

Smoke Bomb

Flash
All creatures have shroud. (They can't be the targets of spells or abilities.)
At the beginning of your upkeep, sacrifice this artifact. When you do, target creature you control can't be blocked this turn.

Haystack

{2}, {T}: Target creature you control phases out. (Treat it and anything attached to it as though they don't exist until your next turn.)

Command Tower

Temple of Triumph

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {R} or {W}.

Nomad Outpost

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

Arbaaz Mir

Whenever Arbaaz Mir or another nontoken historic permanent you control enters, Arbaaz Mir deals 1 damage to each opponent and you gain 1 life. (Artifacts, legendaries, and Sagas are historic.)

Chain Assassination

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.)
Destroy target creature. If another creature died this turn, draw a card.

Reconnaissance

{0}: Remove target attacking creature you control from combat and untap it. (If you activate during end of combat, the creature will untap after it deals combat damage.)

Sol Ring

Bayek of Siwa

Double strike
During your turn, other historic creatures you control have double strike.
Disguise {1}{R}{W} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)

Assassin Initiate

{1}: This creature gains your choice of flying, deathtouch, or lifelink until end of turn.

Brotherhood Ambushers

Freerunning {3}{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.)

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.

The Spear of Leonidas

Whenever equipped creature attacks, choose one —
• Bull Rush — It gains double strike until end of turn.
• Summon — Create Phobos, a legendary 3/2 red Horse creature token.
• Revelation — Discard two cards, then draw two cards.
Equip {2}

Black Market Connections

At the beginning of your first main phase, choose one or more —
• Sell Contraband — Create a Treasure token. You lose 1 life.
• Buy Information — Draw a card. You lose 2 life.
• Hire a Mercenary — Create a 3/2 colorless Shapeshifter creature token with changeling. You lose 3 life. (It is every creature type.)

Temple of Silence

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {W} or {B}.

Sundown Pass

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

Hidden Blade

Flash
When this Equipment enters, attach it to target creature you control. If that creature is an Assassin, it gains deathtouch until end of turn.
Equipped creature gets +1/+0 and has first strike.
Equip {2}

Godless Shrine

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

Kassandra, Eagle Bearer

Haste
When Kassandra enters, search your graveyard, hand, and library for a card named The Spear of Leonidas, put it onto the battlefield, then shuffle.
Whenever a creature you control with a legendary Equipment attached to it deals combat damage to a player, draw a card.

Cover of Darkness

As this enchantment enters, choose a creature type.
Creatures of the chosen type have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

Isolated Chapel

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

Blood Crypt

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

Yggdrasil, Rebirth Engine

When Yggdrasil enters, exile all creature cards from your graveyard.
{T}: Exile the top three cards of your library.
{4}, {T}: Put a creature card exiled with Yggdrasil onto the battlefield under your control. It gains haste until end of turn. Activate only as a sorcery.

Sword of Light and Shadow

Equipped creature gets +2/+2 and has protection from white and from black.
Whenever equipped creature deals combat damage to a player, you gain 3 life and you may return up to one target creature card from your graveyard to your hand.
Equip {2}

Phantom Blade

When this Equipment enters, attach it to up to one target creature you control. Destroy up to one other target creature.
Equipped creature gets +1/+1 and has menace. (It can't be blocked except by two or more creatures.)
Equip {2}

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.

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.

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.)

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.)

Smoldering Marsh

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

Origin of the Hidden Ones

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — This Saga deals 4 damage to any target.
II — Create two 1/1 black Assassin creature tokens with menace.
III — Whenever an Assassin you control attacks this turn, create a 1/1 black Assassin creature token with menace that's tapped and attacking.

Fall of the First Civilization

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — You and target opponent each draw two cards.
II — Exile target artifact an opponent controls.
III — Each player chooses three nonland permanents they control. Destroy all other nonland permanents.

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.

Clifftop Retreat

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

Layla Hassan

First strike
When Layla Hassan enters and whenever one or more Assassins you control deal combat damage to a player, return target historic card from your graveyard to your hand.

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.

Herald's Horn

As this artifact enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Towering Viewpoint

Defender, reach
Leap of Faith — {3}: Target creature gains flying until end of turn.