Fountain of Ichor

{T}: Add one mana of any color.
{3}: Fountain of Ichor becomes a 3/3 Dinosaur artifact creature until end of turn.

Etherium Sculptor

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

Candlekeep Sage

Commander creatures you own have "When this creature enters or leaves the battlefield, draw a card."

Arcane Signet

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

Maverick Thopterist

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
When Maverick Thopterist enters, create two 1/1 colorless Thopter artifact creature tokens with flying.

Izzet Signet

Kenku Artificer

Homunculus Servant — When Kenku Artificer enters, put three +1/+1 counters on up to one target noncreature artifact. That artifact becomes a 0/0 Homunculus artifact creature with flying.

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Ingenious Artillerist

Whenever one or more artifacts you control enter, Ingenious Artillerist deals that much damage to each opponent.

Tavern Brawler

Commander creatures you own have "At the beginning of your upkeep, exile the top card of your library. This creature gets +X/+0 until end of turn, where X is that card's mana value. You may play that card this turn."

Sky Diamond

Koilos Roc

Flash
Flying
When Koilos Roc enters, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Izzet Locket

{T}: Add {U} or {R}.
{U/R}{U/R}{U/R}{U/R}, {T}, Sacrifice Izzet Locket: Draw two cards.

Dire Mimic

Flash
{T}, Sacrifice Dire Mimic: Add one mana of any color.
{3}: Dire Mimic becomes a Shapeshifter artifact creature with base power and toughness 5/5 until end of turn.

Reckless Fireweaver

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

Thoughtcast

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