Malcator's Watcher

Flying, vigilance
When this creature dies, draw a card.

Spire Serpent

Defender
Metalcraft - As long as you control three or more artifacts, this creature gets +2/+2 and can attack as though it didn't have defender.

Lumengrid Drake

Flying
Metalcraft — When this creature enters, if you control three or more artifacts, return target creature to its owner's hand.

Seat of the Synod

Ancient Den

Razortide Bridge

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

Ardent Recruit

Metalcraft - This creature gets +2/+2 as long as you control three or more artifacts.

Thoughtcast

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

Goggles of Night

Whenever equipped creature deals combat damage to a player, scry 1, then draw a card. (To scry 1, look at the top card of your library, then you may put that card on the bottom.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Lens Flare

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Lens Flare deals 5 damage to target attacking or blocking creature.

Plains

Rusted Relic

Metalcraft — This artifact is a 5/5 Golem artifact creature as long as you control three or more artifacts.

Darksteel Citadel

Court Homunculus

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

Chromatic Star

{1}, {T}, Sacrifice this artifact: Add one mana of any color.
When this artifact is put into a graveyard from the battlefield, draw a card.

Auriok Sunchaser

Metalcraft — As long as you control three or more artifacts, this creature gets +2/+2 and has flying.

Myr Enforcer

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

Etherium Sculptor

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

Dragonfly Suit

Flying
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.)