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.

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.)

Leonardo, Sewer Samurai

Sneak {2}{W}{W}
Double strike
During your turn, you may cast creature spells with power or toughness 1 or less from your graveyard. If you cast a spell this way, that creature enters with a finality counter on it. (If a creature with a finality counter on it would die, exile it instead.)

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.)

Have

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.)

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.)

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.

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.

Mountain

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.

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.)

Dark Ritual

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

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.

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.)

Plains

Island

Super Shredder

Menace
Whenever another permanent leaves the battlefield, put a +1/+1 counter on Super Shredder.

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.

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.)

Raphael's Technique

Sneak {2}{R} (You may cast this spell for {2}{R} if you also return an unblocked attacker you control to hand during the declare blockers step.)
Each player may discard their hand and draw seven cards.

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

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.

Bebop & Rocksteady

Whenever Bebop & Rocksteady attack or block, sacrifice a permanent unless you discard a card.

Krang, Master Mind

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
When Krang enters, if you have fewer than four cards in hand, draw cards equal to the difference.
Krang gets +1/+0 for each other artifact you control.