Molder Slug

At the beginning of each player's upkeep, that player sacrifices an artifact of their choice.

Ancient Runes

At the beginning of each player's upkeep, this enchantment deals damage to that player equal to the number of artifacts they control.

Sardian Avenger

First strike, trample
Whenever this creature attacks, it gets +X/+0 until end of turn, where X is the number of artifacts your opponents control.
Whenever an artifact an opponent controls is put into a graveyard from the battlefield, this creature deals 1 damage to that player.

Viridian Revel

Whenever an artifact is put into an opponent's graveyard from the battlefield, you may draw a card.