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.

Turtleshell Changeling

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

Tortoise Formation

Creatures you control gain shroud until end of turn. (They can't be the targets of spells or abilities.)

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.")

Riptide Turtle

Turtles Forever

Search your library and/or outside the game for exactly four legendary creature cards you own with different names, then reveal those cards. An opponent chooses two of them. Put the chosen cards into your hand and shuffle the rest into your library.

Have

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.

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.

Calcite Snapper

Shroud (This creature can't be the target of spells or abilities.)
Landfall — Whenever a land you control enters, you may switch this creature's power and toughness until end of turn.

Turtle-Duck

{3}: Until end of turn, this creature has base power 4 and gains trample.

Archelos, Lagoon Mystic

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

Daring Thunder-Thief

Giant Tortoise

This creature gets +0/+3 as long as it's untapped.

Mistford River Turtle

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

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.

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.

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.

Wormfang Turtle

When this creature enters, exile a land you control.
When this creature leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Aegis Turtle

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.

Cold-Water Snapper

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Turtle-Seals

Vigilance (Attacking doesn't cause this creature to tap.)

Tidepool Turtle

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

Armored Whirl Turtle

Horned Turtle

Giant Turtle

This creature can't attack if it attacked during your last turn.

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.

Hexbane Tortoise

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Enlist (As this creature attacks, you may tap a nonattacking creature you control without summoning sickness. When you do, add its power to this creature's until end of turn.)

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.

Thriving Turtle

When this creature enters, you get {E}{E} (two energy counters).
Whenever this creature attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it.

Angler Turtle

Hexproof
Creatures your opponents control attack each combat if able.

Harried Dash

Create a 1/1 white Rabbit creature token. It gains haste until end of turn.

Steady Tortoise

Ward {2}
Whenever you attack, Steady Tortoise perpetually gets +1/+1. This ability also triggers if Steady Tortoise is in exile.