Battered Golem

Battered Golem doesn't untap during your untap step.
Whenever an artifact enters, you may untap Battered Golem.

Skyline Cascade

Skyline Cascade enters tapped.
When Skyline Cascade enters, target creature an opponent controls doesn't untap during its controller's next untap step.
{T}: Add {U}.

Have

Thoughtcast

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

Darksteel Citadel

Golem Foundry

Whenever you cast an artifact spell, you may put a charge counter on Golem Foundry.
Remove three charge counters from Golem Foundry: Create a 3/3 colorless Golem artifact creature token.

Seat of the Synod

Lonely Sandbar

Lonely Sandbar enters tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Tooth of Chiss-Goria

Flash
Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
{T}: Target creature gets +1/+0 until end of turn.

Machinate

Look at the top X cards of your library, where X is the number of artifacts you control. Put one of those cards into your hand and the rest on the bottom of your library in any order.

Retraction Helix

Until end of turn, target creature gains "{T}: Return target nonland permanent to its owner's hand."

Island

Zephyr Scribe

{U}, {T}: Draw a card, then discard a card.
Whenever you cast a noncreature spell, untap Zephyr Scribe.

Banishing Knack

Scale of Chiss-Goria

Flash
Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
{T}: Target creature gets +0/+1 until end of turn.

Stoic Rebuttal

Metalcraft — This spell costs {1} less to cast if you control three or more artifacts.
Counter target spell.

Drift of Phantasms

Defender (This creature can't attack.)
Flying
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)