Mindstab Thrull

Whenever Mindstab Thrull attacks and isn't blocked, you may sacrifice it. If you do, defending player discards three cards.

Sensory Deprivation

Enchant creature
Enchanted creature gets -3/-0.

Ad Nauseam

Reveal the top card of your library and put that card into your hand. You lose life equal to its mana value. You may repeat this process any number of times.

Phyrexian Unlife

You don't lose the game for having 0 or less life.
As long as you have 0 or less life, all damage is dealt to you as though its source had infect. (Damage is dealt to you in the form of poison counters.)

Black Cat

When Black Cat dies, target opponent discards a card at random.

Terror

Destroy target nonartifact, nonblack creature. It can't be regenerated.

Mindstab

Target player discards three cards.
Suspend 4—{B} (Rather than cast this card from your hand, you may pay {B} and exile it with four time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Lingering Tormentor

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Plagiarize

Until end of turn, if target player would draw a card, instead that player skips that draw and you draw a card.

Treacherous Urge

Target opponent reveals their hand. You may put a creature card from it onto the battlefield under your control. That creature gains haste. Sacrifice it at the beginning of the next end step.

Brisela, Voice of Nightmares

Flying, first strike, vigilance, lifelink
Your opponents can't cast spells with mana value 3 or less.

Transgress the Mind

Devoid (This card has no color.)
Target player reveals their hand. You choose a card from it with mana value 3 or greater and exile that card.