Inventor's Apprentice

This creature gets +1/+1 as long as you control an artifact.

Tolarian Academy

{T}: Add {U} for each artifact you control.

Phyrexian Dragon Engine

Double strike
When this creature enters from your graveyard, you may discard your hand. If you do, draw three cards.
Unearth {3}{R}{R}
(Melds with Mishra, Claimed by Gix.)

Demand Answers

As an additional cost to cast this spell, sacrifice an artifact or discard a card.
Draw two cards.

Combat Courier

{2}, Sacrifice this creature: Draw a card.
Unearth {U} ({U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Chief of the Foundry

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

Smuggler's Copter

Flying
Whenever this Vehicle attacks or blocks, you may draw a card. If you do, discard a card.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

Mountain

Built to Smash

Target attacking creature gets +3/+3 until end of turn. If it's an artifact creature, it gains trample until end of turn.

Gearseeker Serpent

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
{5}{U}: This creature can't be blocked this turn.

Bomat Courier

Haste
Whenever this creature attacks, exile the top card of your library face down. (You can't look at it.)
{R}, Discard your hand, Sacrifice this creature: Put all cards exiled with this creature into their owners' hands.