Donatello, the Brains

If one or more tokens would be created under your control, those tokens plus a Mutagen token are created instead.
Partner—Character select (You can have two commanders if both have this ability.)

Aegis Turtle

Splinter, the Mentor

Menace
Whenever Splinter or another nontoken creature you control leaves the battlefield, create a Mutagen token.
Partner—Character select (You can have two commanders if both have this ability.)

Thunderous Snapper

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

Leonardo, the Balance

Whenever a token you control enters, you may put a +1/+1 counter on each creature you control. Do this only once each turn.
{W}{U}{B}{R}{G}: Creatures you control gain menace, trample, and lifelink until end of turn.
Partner—Character select (You can have two commanders if both have this ability.)

Raphael, Tag Team Tough

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Raphael deals combat damage to a player for the first time each turn, untap all attacking creatures. After this combat phase, there is an additional combat phase.

Angler Turtle

Hexproof
Creatures your opponents control attack each combat if able.

Leonardo, Worldly Warrior

This spell costs {1} less to cast for each creature you control.
Double strike (This creature deals both first-strike and regular combat damage.)

Ticket Tortoise

Defender
When this creature enters, if an opponent controls more lands than you, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Bedrock Tortoise

During your turn, creatures you control have hexproof.
Each creature you control with toughness greater than its power assigns combat damage equal to its toughness rather than its power.

Tidepool Turtle

{2}{U}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Michelangelo, On the Scene

Trample (This creature can deal excess combat damage to the player it's attacking.)
Michelangelo enters with a +1/+1 counter on him for each land you control.
When Michelangelo dies, return this card to your hand.

Ancient Adamantoise

Vigilance, ward {3}
Damage isn't removed from this creature during cleanup steps.
All damage that would be dealt to you and other permanents you control is dealt to this creature instead.
When this creature dies, exile it and create ten tapped Treasure tokens.

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.

Michelangelo, the Heart

Trample
Raid (the Fridge) — At the beginning of your second main phase, if you attacked this turn, put a +1/+1 counter on target creature and create a Food token.
Partner—Character select (You can have two commanders if both have this ability.)

Fecund Greenshell

Reach
As long as you control ten or more lands, creatures you control get +2/+2.
Whenever this creature or another creature you control with toughness greater than its power enters, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. Otherwise, put it into your hand.

Donatello, Rad Scientist

Vigilance (Attacking doesn't cause this creature to tap.)
When Donatello enters, tap up to three target creatures your opponents control. Put a stun counter on each of them. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Dark Ritual

Raphael, the Muscle

Double all damage that creatures you control with counters on them would deal.
When Raphael enters, create a Mutagen token.
Partner—Character select (You can have two commanders if both have this ability.)

Quandrix Cultivator

When this creature enters, you may search your library for a basic Forest or Island card, put it onto the battlefield, then shuffle.

Snapping Voidcraw

Devoid (This card has no color.)
{T}: Add {C}{C}.
{3}{C}, {T}: Draw a card.

Blossoming Tortoise

Whenever this creature enters or attacks, mill three cards, then return a land card from your graveyard to the battlefield tapped.
Activated abilities of lands you control cost {1} less to activate.
Land creatures you control get +1/+1.

Archelos, Lagoon Mystic

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

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.

Heroes in a Half Shell

Vigilance, menace, trample, haste
Whenever one or more Mutants, Ninjas, and/or Turtles you control deal combat damage to a player, put a +1/+1 counter on each of those creatures and draw a card.

Ambling Stormshell

Ward {2}
Whenever this creature attacks, put three stun counters on it and draw three cards. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you cast a Turtle spell, untap this creature.

Donnie & April, Adorkable Duo

When Donnie & April enter, choose one or both. Each mode must target a different player.
• Target player draws two cards.
• Target player returns an artifact, instant, or sorcery card from their graveyard to their hand.

Spikeshell Harrier

When this creature enters, return target creature or Vehicle an opponent controls to its owner's hand. If that opponent's speed is greater than each other player's speed, reduce that opponent's speed by 1. This effect can't reduce their speed below 1.