Spire of Industry

{T}: Add {C}.
{T}, Pay 1 life: Add one mana of any color. Activate only if you control an artifact.

Ornithopter

Snow-Covered Mountain

Arcbound Ravager

Sacrifice an artifact: Put a +1/+1 counter on this creature.
Modular 1 (This creature enters with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Blinkmoth Nexus

{T}: Add {C}.
{1}: This land becomes a 1/1 Blinkmoth artifact creature with flying until end of turn. It's still a land.
{1}, {T}: Target Blinkmoth creature gets +1/+1 until end of turn.

All That Glitters

Enchant creature
Enchanted creature gets +1/+1 for each artifact and/or enchantment you control.

Darksteel Citadel

Etched Champion

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

Sunscorched Desert

When this land enters, it deals 1 damage to target player or planeswalker.
{T}: Add {C}.

Snow-Covered Island

Welding Jar

Sacrifice this artifact: Regenerate target artifact.

Steel Overseer

{T}: Put a +1/+1 counter on each artifact creature you control.

Springleaf Drum

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

Galvanic Blast

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

Master of Etherium

Master of Etherium's power and toughness are each equal to the number of artifacts you control.
Other artifact creatures you control get +1/+1.

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.)

Memnite

Cranial Plating

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

Signal Pest

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