Kitsune, Dragon's Daughter

Vigilance
Whenever Kitsune enters or deals combat damage to a player, you may exchange control of two other target creatures controlled by different players.

Kitsune's Technique

Sneak {1}{U} (You may cast this spell for {1}{U} if you also return an unblocked attacker you control to hand during the declare blockers step.)
Target opponent mills half their library, rounded up.

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.

Metalhead

When Metalhead enters, return up to one other target artifact or creature to its owner's hand.
{R}, Sacrifice another artifact: Put a +1/+1 counter on Metalhead. He gains menace and haste until end of 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.

Mondo Gecko

{1}, Discard a card: Until end of turn, Mondo Gecko becomes the color of your choice and gains hexproof from that color.
Whenever Mondo Gecko deals combat damage to a player, draw a card for each color among permanents you control.

Negate

Mutagen

Ooze Spill

Counter target spell. 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.")

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.

East Wind Avatar

Flying, vigilance
Alliance — Whenever another creature you control enters, this creature gets +1/+0 until end of turn.

Renet, Temporal Apprentice

Flash
When Renet enters, return each other nonland permanent that entered this turn to its owner's hand.

Retro-Mutation

Flash
Enchant creature
Enchanted creature is a Turtle with base power and toughness 0/1. It can't attack and loses all abilities. (It also loses all other creature types.)

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.")

Sewer-veillance Cam

Flash
When this artifact enters or leaves the battlefield, you may tap or untap target creature.
{3}{U}, Sacrifice this artifact: Draw two cards.

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.)

Turtles in Time

Return all creatures to their owners' hands. Each player may shuffle their hand and graveyard into their library, then each player who does draws seven cards.
Exile Turtles in Time.

Teenage Mutant Ninja Turtles