Magistrate's Scepter

{4}, {T}: Put a charge counter on this artifact.
{T}, Remove three charge counters from this artifact: Take an extra turn after this one.

Foundry Inspector

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

Wake the Past

Return all artifact cards from your graveyard to the battlefield. They gain haste until end of turn.

Palladium Myr

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Sol Ring

Alibou, Ancient Witness

Other artifact creatures you control have haste.
Whenever one or more artifact creatures you control attack, Alibou deals X damage to any target and you scry X, where X is the number of tapped artifacts you control.

Dispatch

Tap target creature.
Metalcraft — If you control three or more artifacts, exile that creature.

Gold Myr

Iron Myr

Living Brain, Mechanical Marvel

At the beginning of combat on your turn, target non-Equipment artifact you control becomes an artifact creature with base power and toughness 3/3 until end of turn. Untap it.

Iron Spider, Stark Upgrade

Vigilance
{T}: Put a +1/+1 counter on each artifact creature and/or Vehicle you control.
{2}, Remove two +1/+1 counters from among artifacts you control: Draw a card.

Rustvale Bridge

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

Organic Extinction

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Destroy all nonartifact creatures.

Bronze Guardian

Double strike
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Other artifacts you control have ward {2}.
Bronze Guardian's power is equal to the number of artifacts you control.