Signal Pest

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Signal Pest can't be blocked except by creatures with flying or reach.

Disciple of the Vault

Whenever an artifact is put into a graveyard from the battlefield, you may have target opponent lose 1 life.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Unknown Shores

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Great Furnace

Atog

Sacrifice an artifact: Atog gets +2/+2 until end of turn.

Galvanic Blast

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

Time Sieve

{T}, Sacrifice five artifacts: Take an extra turn after this one.

Vault of Whispers

Thoughtcast

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Draw two cards.

Thopter Assembly

Flying
At the beginning of your upkeep, if you control no Thopters other than Thopter Assembly, return Thopter Assembly to its owner's hand and create five 1/1 colorless Thopter artifact creature tokens with flying.

Vault Skirge

({B/P} can be paid with either {B} or 2 life.)
Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Cranial Plating

Equipped creature gets +1/+0 for each artifact you control.
{B}{B}: Attach Cranial Plating to target creature you control.
Equip {1}

Darksteel Citadel

Shimmering Grotto

Seat of the Synod

Myr Enforcer

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)