Leonardo's Technique

Sneak {1}{W} (You may cast this spell for {1}{W} if you also return an unblocked attacker you control to hand during the declare blockers step.)
Return one or two target creature cards each with mana value 3 or less from your graveyard to the battlefield.

Dark Leo & Shredder

Sneak {W}{B}
Attacking Ninjas you control have deathtouch.
Whenever Dark Leo & Shredder deal combat damage to a player, create a 1/1 black Ninja creature token. Then if you control five or more Ninjas, that player loses half their life, rounded up.

Godless Shrine

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

Exotic Orchard

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

Prehistoric Pet

This creature can't be blocked by creatures with greater power.
{1}{W}, {T}: Return another target creature you control to its owner's hand. Activate only during your turn.

Baleful Strix

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

Shark Shredder, Killer Clone

Sneak {3}{B}{B}
First strike
Whenever Shark Shredder deals combat damage to a player, put up to one target creature card from that player's graveyard onto the battlefield under your control. It enters tapped and attacking that player.

Hallowed Fountain

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

Moon-Circuit Hacker

Ninjutsu {U} ({U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, you may draw a card. If you do, discard a card unless this creature entered this turn.

Raise the Palisade

Choose a creature type. Return all creatures that aren't of the chosen type to their owners' hands.

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.

Plains

Isolated Chapel

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

Thousand-Faced Shadow

Ninjutsu {2}{U}{U} ({2}{U}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Flying
When this creature enters from your hand, if it's attacking, create a token that's a copy of another target attacking creature. The token enters tapped and attacking.

Kaito, Cunning Infiltrator

Whenever a creature you control deals combat damage to a player, put a loyalty counter on Kaito.
+1: Up to one target creature you control can't be blocked this turn. Draw a card, then discard a card.
−2: Create a 2/1 blue Ninja creature token.
−9: You get an emblem with "Whenever a player casts a spell, you create a 2/1 blue Ninja creature token."

Lightning Greaves

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

Sea of Clouds

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

Changeling Outcast

Changeling (This card is every creature type.)
This creature can't block and can't be blocked.

Watery Grave

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

Polluted Delta

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Raffine's Tower

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

Throatseeker

Unblocked attacking Ninjas you control have lifelink.

Ninja's Blades

Job select
Equipped creature gets +1/+1, is a Ninja in addition to its other types, and has "Whenever this creature deals combat damage to a player, draw a card, then discard a card. That player loses life equal to the discarded card's mana value."
Mutsunokami — Equip {2}

Ninja of the Deep Hours

Ninjutsu {1}{U} ({1}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, you may draw a card.

Throat Slitter

Ninjutsu {2}{B} ({2}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, destroy target nonblack creature that player controls.

Arcane Signet

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

Swamp

Silver-Fur Master

Ninjutsu {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Ninjutsu abilities you activate cost {1} less to activate.
Other Ninja and Rogue creatures you control get +1/+1.

Nashi, Moon Sage's Scion

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Nashi deals combat damage to a player, exile the top card of each player's library. Until end of turn, you may play one of those cards. If you cast a spell this way, pay life equal to its mana value rather than paying its mana cost.

Satoru Umezawa

Whenever you activate a ninjutsu ability, look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order. This ability triggers only once each turn.
Each creature card in your hand has ninjutsu {2}{U}{B}.

Command Tower

Taeko, the Patient Avalanche

Taeko enters tapped.
Whenever another creature you control leaves the battlefield, if it didn't die, scry 1 and put a +1/+1 counter on Taeko.
Whenever Taeko attacks, you may pay {U/B}. When you do, target attacking creature can't be blocked this turn.

Drowned Catacomb

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

Morphic Pool

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

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.")

Higure, the Still Wind

Ninjutsu {2}{U}{U} ({2}{U}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Higure deals combat damage to a player, you may search your library for a Ninja card, reveal it, put it into your hand, then shuffle.
{2}: Target Ninja creature can't be blocked this turn.

Ingenious Infiltrator

Ninjutsu {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever a Ninja you control deals combat damage to a player, draw a card.

Island

Patchwork Banner

As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

Dimir Signet

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.)

Negate

Splinter, Radical Rat

If an ability of a Ninja creature you control triggers, that ability triggers an additional time.
{1}{U}: Target Ninja can't be blocked this turn.

Kindred Discovery

As this enchantment enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Fallen Shinobi

Ninjutsu {2}{U}{B} ({2}{U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, that player exiles the top two cards of their library. Until end of turn, you may play those cards without paying their mana costs.

Dovin's Veto

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

Anguished Unmaking

Exile target nonland permanent. You lose 3 life.

Orochi Soul-Reaver

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever one or more creatures you control deal combat damage to a player, create a Treasure token and 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.)

Karai, Future of the Foot

Sneak {2}{W}{B} (You may cast this spell for {2}{W}{B} if you also return an unblocked attacker you control to hand during the declare blockers step. She enters tapped and attacking.)
Whenever Karai deals combat damage to a player, return target creature card from your graveyard to your hand. If her sneak cost was paid this turn, instead return that card to the battlefield.

Swords to Plowshares

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

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Turtle Lair

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a Ninja or Turtle spell.
{3}, {T}: Target Ninja or Turtle can't be blocked this turn.

Reliquary Tower

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

Endless Foot Assault

Squad {1}{W} (As an additional cost to cast this spell, you may pay {1}{W} any number of times. When this enchantment enters, create that many tokens that are copies of it.)
Whenever you attack, for each opponent, create a 1/1 black Ninja creature token that's tapped and attacking that player.

Underground River

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

Talisman of Dominance

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

Turncoat Kunoichi

Sneak {2}{W}{B} (You may cast this spell for {2}{W}{B} if you also return an unblocked attacker you control to hand during the declare blockers step. It enters tapped and attacking.)
When this creature enters, choose target creature an opponent controls. Exile that creature until this creature leaves the battlefield. If this creature's sneak cost was paid, instead exile the chosen creature.

Shipwreck Marsh

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

Moonsnare Specialist

Ninjutsu {2}{U} ({2}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When this creature enters, return up to one target creature to its owner's hand.

Vault of Champions

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

Kindred Dominance

Choose a creature type. Destroy all creatures that aren't of the chosen type.

Glacial Fortress

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

Yuriko, the Tiger's Shadow

Commander ninjutsu {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand or the command zone tapped and attacking.)
Whenever a Ninja you control deals combat damage to a player, reveal the top card of your library and put that card into your hand. Each opponent loses life equal to that card's mana value.

Bloodline Bidding

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.)
Choose a creature type. Return all creature cards of the chosen type from your graveyard to the battlefield.

Mistblade Shinobi

Ninjutsu {U} ({U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, you may return target creature that player controls to its owner's hand.

Prosperous Thief

Ninjutsu {1}{U} ({1}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever one or more Ninja or Rogue creatures you control deal combat damage to a player, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Silent-Blade Oni

Ninjutsu {4}{U}{B} ({4}{U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, look at that player's hand. You may cast a spell from among those cards without paying its mana cost.

Sol Ring

Ninja Teen

(Gain the next level as a sorcery to add its ability.)
Whenever a creature you control leaves the battlefield, each opponent loses 1 life.
{1}{B}: Level 2
Creatures you control get +1/+0 and have menace.
{B}: Level 3
Creature cards in your graveyard have sneak {3}{B}.
You may cast creature spells from your graveyard using their sneak abilities.

Rogue's Passage

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

Super Shredder

Menace
Whenever another permanent leaves the battlefield, put a +1/+1 counter on Super Shredder.

Counterspell

Shredder, Shadow Master

Whenever Shredder attacks a player, for each other opponent, create a token that's a copy of Shredder tapped and attacking that player, except it isn't legendary. Sacrifice those tokens at end of combat.
Whenever Shredder deals combat damage to a player, that player loses half their life, rounded up.

Arcane Sanctum

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

Smoke Shroud

Enchant creature
Enchanted creature gets +1/+1 and has flying.
When a Ninja you control enters, you may return this card from your graveyard to the battlefield attached to that creature.

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Sakashima's Student

Ninjutsu {1}{U} ({1}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
You may have this creature enter as a copy of any creature on the battlefield, except it's a Ninja in addition to its other creature types.

Splinter's Technique

Sneak {1}{B} (You may cast this spell for {1}{B} if you also return an unblocked attacker you control to hand during the declare blockers step.)
Search your library for a card, put that card into your hand, then shuffle.

Moonblade Shinobi

Ninjutsu {2}{U} ({2}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, create a 1/1 blue Illusion creature token with flying.

Mist-Syndicate Naga

Ninjutsu {2}{U} ({2}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, create a token that's a copy of this creature.

Satoru, the Infiltrator

Menace
Whenever Satoru and/or one or more other nontoken creatures you control enter, if none of them were cast or no mana was spent to cast them, draw a card.

Splinter, Hamato Yoshi

Sneak {B} (You may cast this spell for {B} if you also return an unblocked attacker you control to hand during the declare blockers step. He enters tapped and attacking.)
Menace (This creature can't be blocked except by two or more creatures.)
Other Ninjas you control get +1/+1.

Kaito, Bane of Nightmares

Ninjutsu {1}{U}{B} ({1}{U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
During your turn, as long as Kaito has one or more loyalty counters on him, he's a 3/4 Ninja creature and has hexproof.
+1: You get an emblem with "Ninjas you control get +1/+1."
0: Surveil 2. Then draw a card for each opponent who lost life this turn.
−2: Tap target creature. Put two stun counters on it.

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.)

Slither Blade

Void Rend

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

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.