Blood Tyrant

Flying, trample
At the beginning of your upkeep, each player loses 1 life. Put a +1/+1 counter on this creature for each 1 life lost this way.
Whenever a player loses the game, put five +1/+1 counters on this creature.

Garza Zol, Plague Queen

Flying, haste
Whenever a creature dealt damage by Garza Zol this turn dies, put a +1/+1 counter on Garza Zol.
Whenever Garza Zol deals combat damage to a player, you may draw a card.

Evil Twin

You may have this creature enter as a copy of any creature on the battlefield, except it has "{U}{B}, {T}: Destroy target creature with the same name as this creature."

Dimir Doppelganger

{1}{U}{B}: Exile target creature card from a graveyard. This creature becomes a copy of that card, except it has this ability.

Changeling Outcast

Changeling (This card is every creature type.)
This creature can't block and can't be blocked.

Vampire Charmseeker

Assist (Another player can pay up to {6} of this spell's cost.)
Flying
When this creature enters, return target instant, sorcery, or creature card from a graveyard to its owner's hand.

Graveshifter

Changeling (This card is every creature type.)
When this creature enters, you may return target creature card from your graveyard to your hand.

Mirror Image

You may have this creature enter as a copy of a creature you control.

Protean Raider

Raid — If you attacked this turn, you may have this creature enter as a copy of any creature on the battlefield.

Body Double

You may have this creature enter as a copy of any creature card in a graveyard.

Clone

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

Insidious Mist

Hexproof, indestructible
This creature can't block and can't be blocked.
Whenever this creature attacks and isn't blocked, you may pay {2}{B}. If you do, transform it.

Elusive Tormentor

{1}, Discard a card: Transform this creature.

Elusive Tormentor // Insidious Mist

Mirko Vosk, Mind Drinker

Flying
Whenever Mirko Vosk deals combat damage to a player, that player reveals cards from the top of their library until they reveal four land cards, then puts those cards into their graveyard.