Ornithopter

Spellskite

{U/P}: Change a target of target spell or ability to Spellskite. ({U/P} can be paid with either {U} or 2 life.)

Memnite

Foundry Inspector

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

Leaden Myr

Swamp

Etherium Sculptor

Island

Iron Myr

Blightsteel Colossus

Trample, infect, indestructible
If Blightsteel Colossus would be put into a graveyard from anywhere, reveal Blightsteel Colossus and shuffle it into its owner's library instead.

Mishra, Artificer Prodigy

Whenever you cast an artifact spell, you may search your graveyard, hand, and/or library for a card with the same name as that spell and put it onto the battlefield. If you search your library this way, shuffle.

Mountain

Mycosynth Golem

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Artifact creature spells you cast have affinity for artifacts. (They cost {1} less to cast for each artifact you control.)