Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

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.

Midnight Banshee

Wither (This deals damage to creatures in the form of -1/-1 counters.)
At the beginning of your upkeep, put a -1/-1 counter on each nonblack creature.

Vile Entomber

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When this creature enters, search your library for a card, put that card into your graveyard, then shuffle.

Murder

Morgul-Knife Wound

Enchant creature
Enchanted creature gets -3/-0 and has "At the beginning of your upkeep, exile this creature unless you pay 2 life."

Blight Rot

Put four -1/-1 counters on target creature.

Ambush Gigapede

Flash
When this creature enters, target creature an opponent controls gets -2/-2 until end of turn.

Foundry Hornet

Flying
When this creature enters, if you control a creature with a +1/+1 counter on it, creatures your opponents control get -1/-1 until end of turn.

Blowfly Infestation

Whenever a creature dies, if it had a -1/-1 counter on it, put a -1/-1 counter on target creature.

Soul Snuffers

When this creature enters, put a -1/-1 counter on each creature.

Revoke Demise

This spell costs {2} less to cast if it targets a creature card with mana value 3 or less.
Return target creature card from your graveyard to the battlefield. You gain 2 life.

Subtle Strike

Choose one or both —
• Target creature gets -1/-1 until end of turn.
• Put a +1/+1 counter on target creature.

Frozen Shade

{B}: This creature gets +1/+1 until end of turn.

Scavenging Ghoul

At the beginning of each end step, put a corpse counter on this creature for each creature that died this turn.
Remove a corpse counter from this creature: Regenerate this creature.

Despondency

Enchant creature
Enchanted creature gets -2/-0.
When this Aura is put into a graveyard from the battlefield, return it to its owner's hand.

Darkness Descends

Archfiend's Vessel

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
When this creature enters, if it entered from your graveyard or you cast it from your graveyard, exile it. If you do, create a 5/5 black Demon creature token with flying.

Bog Raiders

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Necroskitter

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls with a -1/-1 counter on it dies, you may return that card to the battlefield under your control.

Lost Soul

Arcbound Condor

Flying
Modular 3 (This creature enters with three +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.)
Whenever another artifact you control enters, target creature an opponent controls gets -1/-1 until end of turn.

Carrion Beetles

{2}{B}, {T}: Exile up to three target cards from a single graveyard.

Necrogoyf

Necrogoyf's power is equal to the number of creature cards in all graveyards.
At the beginning of each player's upkeep, that player discards a card.
Madness {1}{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.)

Black Sun's Zenith

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Maha, Its Feathers Night

Flying, trample
Ward—Discard a card.
Creatures your opponents control have base toughness 1.

Sol Ring

Bile-Vial Boggart

When this creature dies, put a -1/-1 counter on up to one target creature.

Disfigure

Target creature gets -2/-2 until end of turn.

Sicken

Enchant creature
Enchanted creature gets -1/-1.
Cycling {2} ({2}, Discard this card: Draw a card.)

Summon: Anima

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I, II, III — Pain — You draw a card and you lose 1 life.
IV — Oblivion — Each opponent sacrifices a creature of their choice and loses 3 life.
Menace

Tragic Banshee

Morbid — When this creature enters, target creature an opponent controls gets -1/-1 until end of turn. If a creature died this turn, that creature gets -13/-13 until end of turn instead.

Massacre Girl, Known Killer

Menace
Creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls dies, if its toughness was less than 1, draw a card.