Poison Counter

Relic Putrescence

Enchant artifact
Whenever enchanted artifact becomes tapped, its controller gets a poison counter.

Skinrender

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

Skithiryx, the Blight Dragon

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{B}: Skithiryx gains haste until end of turn.
{B}{B}: Regenerate Skithiryx.

Ghalma's Warden

Metalcraft — This creature gets +2/+2 as long as you control three or more artifacts.

Tainted Strike

Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Arc Trail

Arc Trail deals 2 damage to any target and 1 damage to any other target.

Assault Strobe

Target creature gains double strike until end of turn. (It deals both first-strike and regular combat damage.)

Barrage Ogre

{T}, Sacrifice an artifact: This creature deals 2 damage to any target.

Blade-Tribe Berserkers

Metalcraft — When this creature enters, if you control three or more artifacts, this creature gets +3/+3 and gains haste until end of turn.

Bloodshot Trainee

{T}: This creature deals 4 damage to target creature. Activate only if this creature's power is 4 or greater.

Cerebral Eruption

Target opponent reveals the top card of their library. Cerebral Eruption deals damage equal to the revealed card's mana value to that player and each creature that player controls. If a land card is revealed this way, return Cerebral Eruption to its owner's hand.

Embersmith

Whenever you cast an artifact spell, you may pay {1}. If you do, this creature deals 1 damage to any target.

Ferrovore

{R}, Sacrifice an artifact: This creature gets +3/+0 until end of turn.

Flameborn Hellion

Haste
This creature attacks each combat if able.

Glimmerpoint Stag

Vigilance
When this creature enters, exile another target permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Furnace Celebration

Whenever you sacrifice another permanent, you may pay {2}. If you do, this enchantment deals 2 damage to any target.

Scars of Mirrodin