The Haunt of Hightower

Flying, lifelink
Whenever The Haunt of Hightower attacks, defending player discards a card.
Whenever a card is put into an opponent's graveyard from anywhere, put a +1/+1 counter on The Haunt of Hightower.

Blazing Specter

Flying, haste
Whenever this creature deals combat damage to a player, that player discards a card.

Black Cat

When this creature dies, target opponent discards a card at random.

Royal Assassin

Urgoros, the Empty One

Flying
Whenever Urgoros deals combat damage to a player, that player discards a card at random. If the player can't, you draw a card.

Bloodhusk Ritualist

Multikicker {B} (You may pay an additional {B} any number of times as you cast this spell.)
When this creature enters, target opponent discards a card for each time it was kicked.

Doomsday Specter

Flying
When this creature enters, return a blue or black creature you control to its owner's hand.
Whenever this creature deals combat damage to a player, look at that player's hand and choose a card from it. The player discards that card.

Nightveil Specter

Flying
Whenever this creature deals combat damage to a player, that player exiles the top card of their library.
You may play lands and cast spells from among cards exiled with this creature.

Guul Draz Specter

Flying
This creature gets +3/+3 as long as an opponent has no cards in hand.
Whenever this creature deals combat damage to a player, that player discards a card.

Archfiend of Spite

Flying
Whenever a source an opponent controls deals damage to this creature, that source's controller loses that much life unless they sacrifice that many permanents of their choice.
Madness {3}{B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Abyssal Specter

Flying
Whenever this creature deals damage to a player, that player discards a card.

Abyssal Nightstalker

Whenever this creature attacks and isn't blocked, defending player discards a card.

Sedraxis Specter

Flying
Whenever this creature deals combat damage to a player, that player discards a card.
Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Alley Grifters

Whenever this creature becomes blocked, defending player discards a card.

Sol Ring

Entropic Specter

Flying
As this creature enters, choose an opponent.
Entropic Specter's power and toughness are each equal to the number of cards in the chosen player's hand.
Whenever this creature deals damage to a player, that player discards a card.

Abyssal Horror

Flying
When this creature enters, target player discards two cards.

Archon of Cruelty

Flying
Whenever this creature enters or attacks, target opponent sacrifices a creature or planeswalker of their choice, discards a card, and loses 3 life. You draw a card and gain 3 life.

Lightning Skelemental

Trample, haste
Whenever this creature deals combat damage to a player, that player discards two cards.
At the beginning of the end step, sacrifice this creature.

Hollow Specter

Flying
Whenever this creature deals combat damage to a player, you may pay {X}. If you do, that player reveals X cards from their hand and you choose one of them. That player discards that card.

Abyssal Nocturnus

Whenever an opponent discards a card, this creature gets +2/+2 and gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Myojin of Night's Reach

Myojin of Night's Reach enters with a divinity counter on it if you cast it from your hand.
Myojin of Night's Reach has indestructible as long as it has a divinity counter on it.
Remove a divinity counter from Myojin of Night's Reach: Each opponent discards their hand.

Angrath, the Flame-Chained

+1: Each opponent discards a card and loses 2 life.
−3: Gain control of target creature until end of turn. Untap it. It gains haste until end of turn. Sacrifice it at the beginning of the next end step if it has mana value 3 or less.
−8: Each opponent loses life equal to the number of cards in their graveyard.

Nicol Bolas, the Arisen

+2: Draw two cards.
−3: Nicol Bolas deals 10 damage to target creature or planeswalker.
−4: Put target creature or planeswalker card from a graveyard onto the battlefield under your control.
−12: Exile all but the bottom card of target player's library.

Nicol Bolas, the Ravager

Flying
When Nicol Bolas enters, each opponent discards a card.
{4}{U}{B}{R}: Exile Nicol Bolas, then return him to the battlefield transformed under his owner's control. Activate only as a sorcery.

Nicol Bolas, the Ravager // Nicol Bolas, the Arisen

Jin-Gitaxias, Core Augur

Flash
At the beginning of your end step, draw seven cards.
Each opponent's maximum hand size is reduced by seven.

Addle

Choose a color. Target player reveals their hand and you choose a card of that color from it. That player discards that card.

Silent Specter

Flying
Whenever this creature deals combat damage to a player, that player discards two cards.
Morph {3}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Kheru Mind-Eater

Menace
Whenever this creature deals combat damage to a player, that player exiles a card from their hand face down.
You may look at cards exiled with this creature, and you may play lands and cast spells from among those cards.

Amnesia

Target player reveals their hand and discards all nonland cards.

Abandon Hope

As an additional cost to cast this spell, discard X cards.
Look at target opponent's hand and choose X cards from it. That player discards those cards.