Necropolis Fiend

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Flying
{X}, {T}, Exile X cards from your graveyard: Target creature gets -X/-X until end of turn.

Plague Mare

This creature can't be blocked by white creatures.
When this creature enters, creatures your opponents control get -1/-1 until end of turn.

Massacre Girl

Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.

Malakir Soothsayer

Cohort — {T}, Tap an untapped Ally you control: You draw a card and you lose 1 life.

Night of Souls' Betrayal

Weed-Pruner Poplar

At the beginning of your upkeep, target creature other than this creature gets -1/-1 until end of turn.

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Filigree Familiar

When this creature enters, you gain 2 life.
When this creature dies, draw a card.

Umezawa's Charm

Choose one —
• Target creature gets +2/+2 until end of turn.
• Target creature gets -1/-1 until end of turn.
• You gain 2 life.

Dusk Legion Zealot

When this creature enters, you draw a card and you lose 1 life.

Suffocating Fumes

Creatures your opponents control get -1/-1 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Ancestral Vengeance

Enchant creature
When this Aura enters, put a +1/+1 counter on target creature you control.
Enchanted creature gets -1/-1.

Kaervek, the Spiteful

Audacious Thief

Whenever this creature attacks, you draw a card and you lose 1 life.

Ambition's Cost

You draw three cards and you lose 3 life.

Armix, Filigree Thrasher

Whenever Armix attacks, you may discard a card. When you do, target creature defending player controls gets -X/-X until end of turn, where X is the number of artifacts you control plus the number of artifact cards in your graveyard.
Partner (You can have two commanders if both have partner.)

Cower in Fear

Creatures your opponents control get -1/-1 until end of turn.

Painful Lesson

Target player draws two cards and loses 2 life.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Briarblade Adept

Whenever this creature attacks, target creature an opponent controls gets -1/-1 until end of turn.
Encore {3}{B} ({3}{B}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Ifnir Deadlands

{T}: Add {C}.
{T}, Pay 1 life: Add {B}.
{2}{B}{B}, {T}, Sacrifice a Desert: Put two -1/-1 counters on target creature an opponent controls. Activate only as a sorcery.

Festergloom

Nonblack creatures get -1/-1 until end of turn.

Annihilate

Destroy target nonblack creature. It can't be regenerated.
Draw a card.

Succumb to Temptation

Bad Deal

You draw two cards and each opponent discards two cards. Each player loses 2 life.

Blood Divination

As an additional cost to cast this spell, sacrifice a creature.
Draw three cards.

Make Obsolete

Nausea

All creatures get -1/-1 until end of turn.

Clockwork Servant

Adamant — When this creature enters, if at least three mana of the same color was spent to cast it, draw a card.