Scheming Symmetry

Choose two target players. Each of them searches their library for a card, then shuffles and puts that card on top.

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.

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.

Fraying Omnipotence

Each player loses half their life, then discards half the cards in their hand, then sacrifices half the creatures they control of their choice. Round up each time.

Fell Specter

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

Prickle Faeries

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

Invasion of Eldraine

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Eldraine enters, target opponent discards two cards.

Invasion of Eldraine // Prickle Faeries

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.

Animus of Night's Reach

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Animus of Night's Reach attacks, it gets +X/+0 until end of turn, where X is the number of creature cards in defending player's graveyard.

The Long Reach of Night

(As this Saga enters and after your draw step, add a lore counter.)
I, II — Each opponent sacrifices a creature of their choice unless they discard a card.
III — Exile this Saga, then return it to the battlefield transformed under your control.

The Long Reach of Night // Animus of Night's Reach

Tainted Remedy

If an opponent would gain life, that player loses that much life instead.

Torment of Scarabs

Enchant player
At the beginning of enchanted player's upkeep, that player loses 3 life unless they sacrifice a nonland permanent of their choice or discard a card.

Implement of Malice

{B}, Sacrifice Implement of Malice: Target player discards a card. Activate only as a sorcery.
When Implement of Malice is put into a graveyard from the battlefield, draw a card.

Swamp

Drainpipe Vermin

When Drainpipe Vermin dies, you may pay {B}. If you do, target player discards a card.