Battered Golem

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

Ornithopter

Steelfin Whale

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Whenever an artifact you control enters, untap Steelfin Whale.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Retraction Helix

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

Reckless Fireweaver

Whenever an artifact you control enters, Reckless Fireweaver deals 1 damage to each opponent.

Island

Molten Tributary

({T}: Add {U} or {R}.)
Molten Tributary enters tapped.

Mountain

Negate

Banishing Knack

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Welding Jar

Sacrifice Welding Jar: Regenerate target artifact.

Mirran Spy

Flying
Whenever you cast an artifact spell, you may untap target creature.