Burglar Rat

When Burglar Rat enters, each opponent discards a card.

Geth's Grimoire

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

Tinybones, Bauble Burglar

Whenever an opponent discards a card, exile it from their graveyard with a stash counter on it.
During your turn, you may play cards you don't own with stash counters on them from exile, and mana of any type can be spent to cast those spells.
{3}{B}, {T}: Each opponent discards a card. Activate only as a sorcery.

Bottomless Pit

At the beginning of each player's upkeep, that player discards a card at random.

Dark Deal

Each player discards all the cards in their hand, then draws that many cards minus one.

Fell Specter

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

Delirium Skeins

Syphon Mind

Each other player discards a card. You draw a card for each card discarded this way.

Vicious Rumors

Vicious Rumors deals 1 damage to each opponent. Each opponent discards a card, then mills a card. You gain 1 life.

Elderfang Disciple

When Elderfang Disciple enters, each opponent discards a card.

Withering Torment

Destroy target creature or enchantment. You lose 2 life.

Let's Play a Game

Delirium — Choose one. If there are four or more card types among cards in your graveyard, choose one or more instead.
• Creatures your opponents control get -1/-1 until end of turn.
• Each opponent discards two cards.
• Each opponent loses 3 life and you gain 3 life.

Seeker's Folly

Choose one —
• Target opponent discards two cards.
• Creatures your opponents control get -1/-1 until end of turn.

Bandit's Talent

(Gain the next level as a sorcery to add its ability.)
When Bandit's Talent enters, each opponent discards two cards unless they discard a nonland card.
{B}: Level 2
At the beginning of each opponent's upkeep, if that player has one or fewer cards in hand, they lose 2 life.
{3}{B}: Level 3
At the beginning of your draw step, draw an additional card for each opponent who has one or fewer cards in hand.