Teenage Mutant Ninja Turtles

Sorcery

Sneak {1}{W} (You may cast this spell for {1}{W} if you also return an unblocked attacker you control to hand during the declare blockers step.)
Return one or two target creature cards each with mana value 3 or less from your graveyard to the battlefield.

Leonardo's Technique

Mutant

Legendary Creature — Cat Mutant Rebel

When Sally Pride enters, create X 2/2 red Mutant creature tokens, where X is the number of nontoken creatures you control.
Whenever Sally Pride attacks, put a +1/+1 counter on each creature you control.

Sally Pride, Lioness Leader

Secret Lair Drop

Legendary Creature — Leviathan Crab

Spells your opponents cast that target Charix cost {2} more to cast.
{3}: Charix gets +X/-X until end of turn, where X is the number of Islands you control.

Charix, the Raging Isle

Legendary Creature — Horror

Whenever a creature you control becomes blocked, you may return it to its owner's hand.
Whenever one or more creatures you control deal combat damage to a player, draw a card.

Grazilaxx, Illithid Scholar

Slug

Legendary Creature — Slug Horror

At the beginning of each end step, put a slime counter on each creature you don't control.
Creatures you don't control get -1/-1 for each slime counter on them.
Whenever a creature you don't control with a slime counter on it dies, create a 1/1 black Slug creature token.
{U}{B}, Sacrifice a Slug: Draw a card.

Toxrill, the Corrosive

Artifact Creature — Construct

This creature enters with three +1/+1 counters on it.
Remove a +1/+1 counter from this creature: It deals 1 damage to any target.

Triskelion

Instant

Dark Ritual

Earthquake deals X damage to each creature without flying and each player.

Earthquake

Legendary Creature — Dog Cat

Whenever you cast a Dog spell, create a 1/1 green Cat creature token.
Whenever you cast a Cat spell, create a 1/1 white Dog creature token.
{R}{G}{W}, {T}: Rin and Seri deals damage to any target equal to the number of Dogs you control. You gain life equal to the number of Cats you control.

Rin and Seri, Inseparable

Kicker {W} (You may pay an additional {W} as you cast this spell.)
Target player can't cast spells this turn. If this spell was kicked, creatures can't attack this turn.

Orim's Chant

({B/P} can be paid with either {B} or 2 life.)
Target creature gets -5/-5 until end of turn.

Dismember

Creature — Shapeshifter

You may have this creature enter as a copy of any creature on the battlefield.

Clone

Treasure

Enchantment — Aura

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")