Panic Spellbomb

{T}, Sacrifice this artifact: Target creature can't block this turn.
When this artifact is put into a graveyard from the battlefield, you may pay {R}. If you do, draw a card.

Darksteel Axe

Indestructible (Effects that say "destroy" don't destroy this artifact.)
Equipped creature gets +2/+0.
Equip {2}

Galvanic Blast

Galvanic Blast deals 2 damage to any target.
Metalcraft — Galvanic Blast deals 4 damage instead if you control three or more artifacts.

Mountain

Glint Hawk

Flying
When this creature enters, sacrifice it unless you return an artifact you control to its owner's hand.

Myrsmith

Whenever you cast an artifact spell, you may pay {1}. If you do, create a 1/1 colorless Myr artifact creature token.

Plains

Auriok Edgewright

Metalcraft — This creature has double strike as long as you control three or more artifacts.

Etched Champion

Metalcraft — This creature has protection from each color as long as you control three or more artifacts.

Auriok Sunchaser

Metalcraft — As long as you control three or more artifacts, this creature gets +2/+2 and has flying.

Accorder's Shield

Equipped creature gets +0/+3 and has vigilance. (Attacking doesn't cause it to tap.)
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.