Sewer-veillance Cam

Flash
When this artifact enters or leaves the battlefield, you may tap or untap target creature.
{3}{U}, Sacrifice this artifact: Draw two cards.

Island

Bespoke Bō

When this Equipment enters, return up to one other target nonland permanent to its owner's hand.
Equipped creature gets +2/+1 and has vigilance.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Ooze Spill

Counter target spell. Create a Mutagen token. (It's an artifact with "{1}, {T}, Sacrifice this token: Put a +1/+1 counter on target creature. Activate only as a sorcery.")

Escape Tunnel

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
{T}, Sacrifice this land: Target creature with power 2 or less can't be blocked this turn.

Donatello, Way with Machines

Flying
Whenever an artifact you control enters, put a +1/+1 counter on Donatello.

The Neutrinos

Flying
Alliance — Whenever another creature you control enters, The Neutrinos get +1/+0 until end of turn.
Whenever The Neutrinos attack, exile up to one target creature you own, then return it to the battlefield under your control tapped and attacking.

Go Ninja Go

Choose one or both —
• Exile target creature you control, then return it to the battlefield under its owner's control.
• Go Ninja Go deals damage equal to the greatest power among creatures you control to target creature an opponent controls.

Casey Jones, Jury-Rig Justiciar

Haste
When Casey Jones enters, look at the top four cards of your library. You may reveal an artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Slithering Cryptid

When this creature enters, create a Mutagen token. (It's an artifact with "{1}, {T}, Sacrifice this token: Put a +1/+1 counter on target creature. Activate only as a sorcery.")

Null Group Biological Assets

During your turn, this creature has first strike.
Whenever this creature attacks, you may discard a card. If you do, draw a card.

TCRI Building

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {R}.

Mountain

Metalhead

When Metalhead enters, return up to one other target artifact or creature to its owner's hand.
{R}, Sacrifice another artifact: Put a +1/+1 counter on Metalhead. He gains menace and haste until end of turn.

Rock Soldiers

When this creature enters, destroy up to one target noncreature artifact.

Negate

Utrom Scientists

When this creature enters, tap up to one target creature and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Mouser Attack!

Choose one —
• Create a 1/1 colorless Robot artifact creature token.
• Target creature gets +3/+0 and gains first strike until end of turn.

Raphael, Tough Turtle

Alliance — Whenever another creature you control enters, Raphael deals 1 damage to target opponent.

Quintessential Katana

Equipped creature gets +1/+1 and has "Whenever this creature deals combat damage, untap it and you gain 2 life."
Whenever a Ninja you control enters, you may attach this Equipment to it.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Grounded for Life

This spell costs {3} less to cast if it targets a tapped creature.
Destroy target creature.

Buzz Bots

Flying, vigilance
When this creature dies, draw a card.

April O'Neil, Hacktivist

At the beginning of your end step, draw a card for each card type among spells you've cast this turn.

Mechanized Ninja Cavalry

When this creature enters, create a 1/1 colorless Robot artifact creature token.

General Traag, Heart of Stone

Trample
When General Traag enters, you may sacrifice another artifact. When you do, General Traag deals 4 damage to target creature.

Uneasy Alliance

Enchant creature
Enchanted creature can't attack or block.
{5}, Sacrifice this Aura: Exile enchanted creature. You create a 1/1 black Ninja creature token. Activate only as a sorcery.