Ornithopter

Carapace Forger

Metalcraft — Carapace Forger gets +2/+2 as long as you control three or more artifacts.

Forest

Galvanic Blast

Galvanic Blast deals 2 damage to any target.
Metalcraft — Galvanic Blast deals 4 damage instead if you control three or more artifacts.

Kuldotha Rebirth

As an additional cost to cast this spell, sacrifice an artifact.
Create three 1/1 red Goblin creature tokens.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Inventor's Goggles

Equipped creature gets +1/+2.
Whenever an Artificer you control enters, you may attach Inventor's Goggles to it.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Slagwoods Bridge

Slagwoods Bridge enters tapped.
Indestructible
{T}: Add {R} or {G}.

Mirran Mettle

Target creature gets +2/+2 until end of turn.
Metalcraft — That creature gets +4/+4 until end of turn instead if you control three or more artifacts.

Great Furnace

Voldaren Epicure

When Voldaren Epicure enters, it deals 1 damage to each opponent. Create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")

Tree of Tales

Mountain

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Sweatworks Brawler

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