Great Furnace

Mountain

Darksteel Colossus

Trample, indestructible
If Darksteel Colossus would be put into a graveyard from anywhere, reveal Darksteel Colossus and shuffle it into its owner's library instead.

Energy Chamber

At the beginning of your upkeep, choose one —
• Put a +1/+1 counter on target artifact creature.
• Put a charge counter on target noncreature artifact.

Coretapper

{T}: Put a charge counter on target artifact.
Sacrifice Coretapper: Put two charge counters on target artifact.

Needlebug

Platinum Angel

Flying
You can't lose the game and your opponents can't win the game.

Mycosynth Golem

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Artifact creature spells you cast have affinity for artifacts. (They cost {1} less to cast for each artifact you control.)

Furnace Dragon

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When Furnace Dragon enters the battlefield, if you cast it from your hand, exile all artifacts.

Slobad, Goblin Tinkerer

Sacrifice an artifact: Target artifact gains indestructible until end of turn.

Krark-Clan Shaman

Sacrifice an artifact: Krark-Clan Shaman deals 1 damage to each creature without flying.

Darksteel Citadel

Forge Armor

As an additional cost to cast this spell, sacrifice an artifact.
Put X +1/+1 counters on target creature, where X is the sacrificed artifact's mana value.

Drooling Ogre

Whenever a player casts an artifact spell, that player gains control of Drooling Ogre. (This effect lasts indefinitely.)