Ornithopter

Chief of the Foundry

Other artifact creatures you control get +1/+1.

Etherium Sculptor

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

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.

Riddlesmith

Whenever you cast an artifact spell, you may draw a card. If you do, discard a card.

Sai, Master Thopterist

Whenever you cast an artifact spell, create a 1/1 colorless Thopter artifact creature token with flying.
{1}{U}, Sacrifice two artifacts: Draw a card.

Threefold Thunderhulk

Threefold Thunderhulk enters with three +1/+1 counters on it.
Whenever Threefold Thunderhulk enters or attacks, create a number of 1/1 colorless Gnome artifact creature tokens equal to its power.
{2}, Sacrifice another artifact: Put a +1/+1 counter on Threefold Thunderhulk.

Foundry Inspector

Steel Overseer

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

Vedalken Archmage

Whenever you cast an artifact spell, draw a card.