Crovax, Ascendant Hero

Other white creatures get +1/+1.
Nonwhite creatures get -1/-1.
Pay 2 life: Return Crovax, Ascendant Hero to its owner's hand.

Engineered Plague

As Engineered Plague enters the battlefield, choose a creature type.
All creatures of the chosen type get -1/-1.

Curse of Death's Hold

Enchant player
Creatures enchanted player controls get -1/-1.

Heartless Summoning

Creature spells you cast cost {2} less to cast.
Creatures you control get -1/-1.

Toxrill, the Corrosive

At the beginning of each end step, put a slime counter on each creature you don't control.
Creatures you don't control get -1/-1 for each slime counter on them.
Whenever a creature you don't control with a slime counter on it dies, create a 1/1 black Slug creature token.
{U}{B}, Sacrifice a Slug: Draw a card.

Ethereal Absolution

Creatures you control get +1/+1.
Creatures your opponents control get -1/-1.
{2}{W}{B}: Exile target card from an opponent's graveyard. If it was a creature card, you create a 1/1 white and black Spirit creature token with flying.

Ascendant Evincar

Flying (This creature can't be blocked except by creatures with flying or reach.)
Other black creatures get +1/+1.
Nonblack creatures get -1/-1.

Always Watching

Nontoken creatures you control get +1/+1 and have vigilance.

Kaervek, the Spiteful

Smog Elemental

Flying
Creatures with flying your opponents control get -1/-1.

Stronghold Taskmaster

The Flesh Is Weak

When The Flesh Is Weak enters the battlefield, put a +1/+1 counter on each creature you control.
Creatures you control with +1/+1 counters on them are artifacts in addition to their other types.
Nonartifact creatures get -1/-1.

Plague Engineer

Deathtouch
As Plague Engineer enters the battlefield, choose a creature type.
Creatures of the chosen type your opponents control get -1/-1.