Megrim

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

Liliana's Caress

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

Cephalid Broker

{T}: Target player draws two cards, then discards two cards.

Hymn to Tourach

Target player discards two cards at random.

Geth's Grimoire

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

Dimir Cluestone

{T}: Add {U} or {B}.
{U}{B}, {T}, Sacrifice this artifact: Draw a card.

Hypnotic Specter

Flying
Whenever this creature deals damage to an opponent, that player discards a card at random.

Dimir Guildgate

This land enters tapped.
{T}: Add {U} or {B}.

Rackling

At the beginning of each opponent's upkeep, this creature deals X damage to that player, where X is 3 minus the number of cards in their hand.

Island

Recoil

Return target permanent to its owner's hand. Then that player discards a card.

Ostracize

Target opponent reveals their hand. You choose a creature card from it. That player discards that card.

Swamp

Urza's Guilt

Each player draws two cards, then discards three cards, then loses 4 life.

Ravenous Rats

When this creature enters, target opponent discards a card.

Screeching Buzzard

Flying
When this creature dies, each opponent discards a card.

Wistful Thinking

Target player draws two cards, then discards four cards.

The Rack

As this artifact enters, choose an opponent.
At the beginning of the chosen player's upkeep, this artifact deals X damage to that player, where X is 3 minus the number of cards in their hand.

Murder

Lore Broker

{T}: Each player draws a card, then discards a card.

Lonely Sandbar

This land enters tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)