Slay

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

Gloom

White spells cost {3} more to cast.
Activated abilities of white enchantments cost {3} more to activate.

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.

Deathmark

Dunerider Outlaw

Protection from green
At the beginning of each end step, if Dunerider Outlaw dealt damage to an opponent this turn, put a +1/+1 counter on it.

Bereavement

Whenever a green creature dies, its controller discards a card.

Deathgrip

Eastern Paladin

{B}{B}, {T}: Destroy target green creature.

Painter's Servant

As Painter's Servant enters the battlefield, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

Virtue's Ruin

Thrull Wizard

{1}{B}: Counter target black spell unless that spell's controller pays {B} or {3}.

Slithery Stalker

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
When Slithery Stalker enters the battlefield, exile target green or white creature an opponent controls.
When Slithery Stalker leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Irini Sengir

Green enchantment spells and white enchantment spells cost {2} more to cast.

Yawgmoth's Edict

Whenever an opponent casts a white spell, that player loses 1 life and you gain 1 life.

Stromgald Cabal

{T}, Pay 1 life: Counter target white spell.

Nature's Ruin

Swamp

Distorting Lens

{T}: Target permanent becomes the color of your choice until end of turn.

Perish

Destroy all green creatures. They can't be regenerated.

Soot Imp

Flying
Whenever a player casts a nonblack spell, that player loses 1 life.

Marauding Knight

Protection from white
Marauding Knight gets +1/+1 for each Plains your opponents control.