Canata Katana

Eater of Virtue

Whenever equipped creature dies, exile it.
Equipped creature gets +2/+0. 
As long as a card exiled with Eater of Virtue has flying, equipped creature has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, and vigilance.
Equip {1}

Whenever equipped creature dies, exile it.
Equipped creature gets +2/+0.
As long as a card exiled with Eater of Virtue has flying, equipped creature has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, and vigilance.
Equip {1}

Nym's scholars defended their tiny nation with spell-weaving faeries.

Snapcaster Mage

Flash
When this creature enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Zidane, Tantalus Thief // Zidane, Tantalus Thief

Zidane, Tantalus Thief

When Zidane enters, gain control of target creature an opponent controls until end of turn. Untap it. It gains lifelink and haste until end of turn.
Whenever an opponent gains control of a permanent from you, you create a Treasure token.

Sutina, Speaker of the Tajuru

When Sutina enters, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Whenever Sutina attacks, you may return a land you control to its owner's hand. When you do, put a +1/+1 counter on target creature.

Ivora, Insatiable Heir

Trample
When Ivora enters and whenever it deals combat damage to a player, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")
Whenever you discard a card, put a +1/+1 counter on Ivora.

Spark Double

You may have this creature enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Sneak Attack

{R}: You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice the creature at the beginning of the next end step.

"Let me give you a hand. He won't be needing it; he's left-handed. Also dead."

Stitcher's Supplier

When this creature enters or dies, mill three cards. (Put the top three cards of your library into your graveyard.)

Getting caught was bad enough, but being rolled to the detention center was by far the worst part.

Arrest

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.