Palladium Myr

Sol Ring

Arcane Signet

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

Etched Champion

Metalcraft — Etched Champion has protection from each color as long as you control three or more artifacts.

Memnarch

{1}{U}{U}: Target permanent becomes an artifact in addition to its other types. (This effect lasts indefinitely.)
{3}{U}: Gain control of target artifact. (This effect lasts indefinitely.)

Foundry Inspector

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