Mox Opal

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

Ornithopter

Darksteel Juggernaut

Indestructible
Darksteel Juggernaut's power and toughness are each equal to the number of artifacts you control.
This creature attacks each combat if able.

Thoughtcast

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

Darksteel Citadel

Ensoul Artifact

Enchant artifact
Enchanted artifact is a creature with base power and toughness 5/5 in addition to its other types.

Etherium Sculptor

Artifact spells you cast cost {1} less to cast.

Reconstruction

Return target artifact card from your graveyard to your hand.

Goldmire Bridge

This land enters tapped.
Indestructible
{T}: Add {W} or {B}.

Razortide Bridge

This land enters tapped.
Indestructible
{T}: Add {W} or {U}.

Steel Overseer

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

Ancient Den

Island

Mistvault Bridge

This land enters tapped.
Indestructible
{T}: Add {U} or {B}.

Seat of the Synod

Scourglass

{T}, Sacrifice this artifact: Destroy all permanents except for artifacts and lands. Activate only during your upkeep.

Broodstar

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
Broodstar's power and toughness are each equal to the number of artifacts you control.

Vault of Whispers

Glaze Fiend

Flying
Whenever another artifact you control enters, this creature gets +2/+2 until end of turn.

Phyrexian Metamorph

({U/P} can be paid with either {U} or 2 life.)
You may have this creature enter as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types.