Have

Foot Elite

Whenever this creature attacks, another target creature you control gets +1/+0 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Zoo Escapees

When this creature leaves the battlefield, 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.")

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.

Mind Transfer Protocol

Until end of turn, target artifact or creature becomes an artifact creature with base power and toughness 4/5.
Draw a card.

Frog Butler

Deathtouch
{T}: Add one mana of any color.
{2}: This creature gains reach until end of turn.

Stockman, Mad Fly-entist

Flying
When Stockman enters, draw a card, then discard a card.
Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Crustacean Commando

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.")

Plains

Slithering Cryptid

Michelangelo's Technique

Sneak {3}{G} (You may cast this spell for {3}{G} if you also return an unblocked attacker you control to hand during the declare blockers step.)
Look at the top eight cards of your library. Put up to two creature cards with total mana value 6 or less from among them onto the battlefield and the rest on the bottom of your library in a random order.

Forest

Mutagen

{1}, {T}, Sacrifice this token: Put a +1/+1 counter on target creature. Activate only as a sorcery.

Mutant Chain Reaction

Destroy up to one target artifact, enchantment, or creature with flying. 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.")

Hamato Guardian Stance

Target creature gets +1/+3 and gains flying until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Grounded for Life

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

Lessons from Life

Draw three cards. You may put a land card from your hand onto the battlefield tapped.

Primordial Pachyderm

Reach, trample
When this creature enters, you gain 2 life.

Return to the Sewers

Target creature's owner puts it on their choice of the top or bottom of their library. You 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.")

Action News Crew

Vigilance
Channel — {6}, Discard this card: Put a +1/+1 counter on each creature you control. Draw a card.

Cowabunga!

Look at the top four cards of your library. You may reveal a Mutant, Ninja, Turtle, or land card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Ray Fillet, Man Ray

Flying
When Ray Fillet 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.")
{2}, Remove a +1/+1 counter from a creature you control: Draw a card.

Island

Novel Nunchaku

When this Equipment enters, attach it to target creature you control. When you do, equipped creature fights up to one target creature an opponent controls. (Each deals damage equal to its power to the other.)
Equipped creature gets +1/+1 and has trample.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Punk Frogs

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)

Guac & Marshmallow Pizza

Flash
When this artifact enters, target creature gets +2/+2 until end of turn. Untap it.
{2}, {T}, Sacrifice this artifact: You gain 3 life.

April O'Neil, Kunoichi Trainee

When April O'Neil enters, 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.)
April O'Neil can't be blocked by creatures with power 3 or greater.