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.)

Howltooth Hollow

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
This land enters tapped.
{T}: Add {B}.
{B}, {T}: You may play the exiled card without paying its mana cost if each player has no cards in hand.

Hollowborn Barghest

At the beginning of your upkeep, if you have no cards in hand, each opponent loses 2 life.
At the beginning of each opponent's upkeep, if that player has no cards in hand, they lose 2 life.

Harvest Fear

Target opponent discards two cards. (Then exile this card. You may cast the creature later from exile.)

Reaper of Night

Whenever this creature attacks, if defending player has two or fewer cards in hand, it gains flying until end of turn.

Reaper of Night // Harvest Fear

Waste Not

Whenever an opponent discards a creature card, create a 2/2 black Zombie creature token.
Whenever an opponent discards a land card, add {B}{B}.
Whenever an opponent discards a noncreature, nonland card, draw a card.

Liliana's Caress

Whenever an opponent discards a card, that player loses 2 life.

Nath of the Gilt-Leaf

At the beginning of your upkeep, you may have target opponent discard a card at random.
Whenever an opponent discards a card, you may create a 1/1 green Elf Warrior creature token.

Megrim

Whenever an opponent discards a card, this enchantment deals 2 damage to that player.

Quest for the Nihil Stone

Whenever an opponent discards a card, you may put a quest counter on this enchantment.
At the beginning of each opponent's upkeep, if that player has no cards in hand and this enchantment has two or more quest counters on it, you may have that player lose 5 life.

Raiders' Wake

Whenever an opponent discards a card, that player loses 2 life.
Raid — At the beginning of your end step, if you attacked this turn, target opponent discards a card.

Geth's Grimoire

Whenever an opponent discards a card, you may draw a card.

Pulse of the Dross

Target player reveals three cards from their hand and you choose one of them. That player discards that card. Then if that player has more cards in hand than you, return Pulse of the Dross to its owner's hand.

Davriel, Rogue Shadowmage

At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, Davriel deals 2 damage to them.
−1: Target player discards a card.

Blood Scrivener

If you would draw a card while you have no cards in hand, instead you draw two cards and you lose 1 life.

Sangromancer

Flying
Whenever a creature an opponent controls dies, you may gain 3 life.
Whenever an opponent discards a card, you may gain 3 life.

Tinybones, Trinket Thief

At the beginning of each end step, if an opponent discarded a card this turn, you draw a card and you lose 1 life.
{4}{B}{B}: Each opponent with no cards in hand loses 10 life.

Paupers' Cage

At the beginning of each opponent's upkeep, if that player has two or fewer cards in hand, this artifact deals 2 damage to that player.

Shrieking Affliction

At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, they lose 3 life.

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.

Fell Specter

Flying
When this creature enters, target opponent discards a card.
Whenever an opponent discards a card, that player loses 2 life.

Asylum Visitor

At the beginning of each player's upkeep, if that player has no cards in hand, you draw a card and you lose 1 life.
Madness {1}{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.)

Stabwhisker the Odious

At the beginning of each opponent's upkeep, that player loses 1 life for each card fewer than three in their hand.

Nezumi Shortfang

{1}{B}, {T}: Target opponent discards a card. Then if that player has no cards in hand, flip this creature.