Thought Vessel

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

Meandering Towershell

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever this creature attacks, exile it. Return it to the battlefield under your control tapped and attacking at the beginning of the declare attackers step on your next turn.

Beast Within

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

Wandering Tombshell

Command Tower

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

Runed Stalactite

Equipped creature gets +1/+1 and is every creature type.
Equip {2}

Acidic Slime

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When this creature enters, destroy target artifact, enchantment, or land.

Turn into a Pumpkin

Return target nonland permanent to its owner's hand. Draw a card.
Adamant — If at least three blue mana was spent to cast this spell, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Dimir Signet

Curse of the Swine

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

Hinterland Harbor

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

Silburlind Snapper

This creature can't attack unless you've cast a noncreature spell this turn.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Nurturing Peatland

{T}, Pay 1 life: Add {B} or {G}.
{1}, {T}, Sacrifice this land: 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.

Rhox

You may have this creature assign its combat damage as though it weren't blocked.
{2}{G}: Regenerate this creature. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Ninja of the New Moon

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.)

Ninja's Kunai

Equipped creature has "{1}, {T}, Sacrifice Ninja's Kunai: Ninja's Kunai deals 3 damage to any target."
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Universal Automaton

Changeling (This card is every creature type.)

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.

Simic Signet

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.

Woodland Changeling

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.

Emperor Crocodile

When you control no other creatures, sacrifice this creature.

Azra Smokeshaper

Ninjutsu {1}{B} ({1}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When this creature enters, target creature you control gains indestructible until end of turn.

Colossal Skyturtle

Flying, ward {2}
Channel — {2}{G}, Discard this card: Return target card from your graveyard to your hand.
Channel — {1}{U}, Discard this card: Return target creature to its owner's hand.

Frogify

Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1. (It loses all other card types and creature types.)

Phantom Ninja

Steelbane Hydra

This creature enters with X +1/+1 counters on it.
{2}{G}, Remove a +1/+1 counter from this creature: Destroy target artifact or enchantment.

Experiment Kraj

Experiment Kraj has all activated abilities of each other creature with a +1/+1 counter on it.
{T}: Put a +1/+1 counter on target creature.

Dragon Turtle

Flash
Drag Below — When this creature enters, tap it and up to one target creature an opponent controls. They don't untap during their controllers' next untap steps.

Sol Ring

Arcane Signet

Krosan Grip

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Destroy target artifact or enchantment.

Biogenic Upgrade

Distribute three +1/+1 counters among one, two, or three target creatures, then double the number of +1/+1 counters on each of those creatures.

Urban Evolution

Draw three cards. You may play an additional land this turn.

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.

Mistford River Turtle

Whenever this creature attacks, another target attacking non-Human creature can't be blocked this turn.

Reliquary Tower

Fathom Mage

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever a +1/+1 counter is put on this creature, you may draw a card.

Gutter Grime

Whenever a nontoken creature you control dies, put a slime counter on this enchantment, then create a green Ooze creature token with "This token's power and toughness are each equal to the number of slime counters on Gutter Grime."

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.

Scavenging Ooze

{G}: Exile target card from a graveyard. If it was a creature card, put a +1/+1 counter on this creature and you gain 1 life.

Lotus Cobra

Landfall — Whenever a land you control enters, add one mana of any color.

Kiora's Follower

Seedborn Muse

Untap all permanents you control during each other player's untap step.

Tideforce Elemental

{U}, {T}: You may tap or untap another target creature.
Landfall — Whenever a land you control enters, you may untap this creature.

Extract Brain

Target opponent chooses X cards from their hand. Look at those cards. You may cast a spell from among them without paying its mana cost.

Thunderous Snapper

Whenever you cast a spell with mana value 5 or greater, draw a card.

Archelos, Lagoon Mystic

As long as Archelos is tapped, other permanents enter tapped.
As long as Archelos is untapped, other permanents enter untapped.

Swamp

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.

Angler Turtle

Hexproof
Creatures your opponents control attack each combat if able.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Counterspell

Island

Kappa Tech-Wrecker

Ninjutsu {1}{G}
This creature enters with a deathtouch counter on it.
Whenever this creature deals combat damage to a player, you may remove a deathtouch counter from it. When you do, exile target artifact or enchantment that player controls.

Forest

Biting-Palm Ninja

Ninjutsu {2}{B}
This creature enters with a menace counter on it.
Whenever this creature deals combat damage to a player, you may remove a menace counter from it. When you do, that player reveals their hand and you choose a nonland card from it. Exile that card.

Turtleshell Changeling

Changeling (This card is every creature type.)
{1}{U}: Switch this creature's power and toughness until end of turn.

Go for the Throat

Exotic Orchard

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

End-Raze Forerunners

Vigilance, trample, haste
When this creature enters, other creatures you control get +2/+2 and gain vigilance and trample until end of turn.

Saryth, the Viper's Fang

Other tapped creatures you control have deathtouch.
Other untapped creatures you control have hexproof.
{1}, {T}: Untap another target creature or land you control.

Simic Guildgate

This land enters tapped.
{T}: Add {G} or {U}.

Sai of the Shinobi

Equipped creature gets +1/+1.
Whenever a creature you control enters, you may attach this Equipment to it.
Equip {2}

Golgari Signet

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To 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.)