Skinrender

When this creature enters, put three -1/-1 counters on target creature.

Dragonskull Summit

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Fume Spitter

Sacrifice this creature: Put a -1/-1 counter on target creature.

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.

Terminate

Destroy target creature. It can't be regenerated.

Puncture Blast

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Puncture Blast deals 3 damage to any target.

The Scorpion God

Whenever a creature with a -1/-1 counter on it dies, draw a card.
{1}{B}{R}: Put a -1/-1 counter on another target creature.
When The Scorpion God dies, return it to its owner's hand at the beginning of the next end step.

Rustrazor Butcher

First strike
Wither (This deals damage to creatures in the form of -1/-1 counters.)

Black Sun's Zenith

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

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Flamekin Harbinger

When this creature enters, you may search your library for an Elemental card, reveal it, then shuffle and put that card on top.

Swamp

Kulrath Knight

Flying
Wither (This deals damage to creatures in the form of -1/-1 counters.)
Creatures your opponents control with counters on them can't attack or block.

Nest of Scarabs

Whenever you put one or more -1/-1 counters on a creature, create that many 1/1 black Insect creature tokens.

Mountain

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.