Orzhov Signet

Liberator, Urza's Battlethopter

Flash
Flying
You may cast colorless spells and artifact spells as though they had flash.
Whenever you cast a spell, if the amount of mana spent to cast that spell is greater than Liberator, Urza's Battlethopter's power, put a +1/+1 counter on Liberator.

Kayla's Music Box

{W}, {T}: Look at the top card of your library, then exile it face down. (You may look at it any time.)
{T}: Until end of turn, you may play cards you own exiled with Kayla's Music Box.

Dragonspark Reactor

Whenever Dragonspark Reactor or another artifact you control enters, put a charge counter on Dragonspark Reactor.
{4}, Sacrifice Dragonspark Reactor: It deals damage equal to the number of charge counters on it to target player and that much damage to up to one target creature.

Clock of Omens

Tap two untapped artifacts you control: Untap target artifact.

Pia Nalaar, Consul of Revival

Thopters you control have haste.
Whenever you play a land from exile or cast a spell from exile, create a 1/1 colorless Thopter artifact creature token with flying.

Arcbound Shikari

First strike
When Arcbound Shikari enters, put a +1/+1 counter on each other artifact creature you control.
Modular 2 (This creature enters with two +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Rakdos Signet

Alibou, Ancient Witness

Other artifact creatures you control have haste.
Whenever one or more artifact creatures you control attack, Alibou, Ancient Witness deals X damage to any target and you scry X, where X is the number of tapped artifacts you control.

Liquimetal Torque

{T}: Add {C}.
{T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

Oni-Cult Anvil

Whenever one or more artifacts you control leave the battlefield during your turn, create a 1/1 colorless Construct artifact creature token. This ability triggers only once each turn.
{T}, Sacrifice an artifact: Oni-Cult Anvil deals 1 damage to each opponent. You gain 1 life.

Reckless Fireweaver

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

Hope of Ghirapur

Flying
Sacrifice Hope of Ghirapur: Until your next turn, target player who was dealt combat damage by Hope of Ghirapur this turn can't cast noncreature spells.

Metallic Mimic

As Metallic Mimic enters, choose a creature type.
Metallic Mimic is the chosen type in addition to its other types.
Each other creature you control of the chosen type enters with an additional +1/+1 counter on it.

Jan Jansen, Chaos Crafter

Haste
{T}, Sacrifice an artifact creature: Create two Treasure tokens.
{T}, Sacrifice a noncreature artifact: Create two 1/1 colorless Construct artifact creature tokens.

Prosper, Tome-Bound

Deathtouch
Mystic Arcanum — At the beginning of your end step, exile the top card of your library. Until the end of your next turn, you may play that card.
Pact Boon — Whenever you play a card from exile, create a Treasure token.

Goblin Welder

{T}: Choose target artifact a player controls and target artifact card in that player's graveyard. If both targets are still legal as this ability resolves, that player simultaneously sacrifices the artifact and returns the artifact card to the battlefield.

Losheel, Clockwork Scholar

Prevent all combat damage that would be dealt to attacking artifact creatures you control.
Whenever one or more artifact creatures you control enter, draw a card. This ability triggers only once each turn.

Steel Overseer

{T}: Put a +1/+1 counter on each artifact creature you control.

Scrap Trawler

Whenever Scrap Trawler or another artifact you control is put into a graveyard from the battlefield, return to your hand target artifact card in your graveyard with lesser mana value.

Oswald Fiddlebender

Magical Tinkering — {W}, {T}, Sacrifice an artifact: Search your library for an artifact card with mana value equal to 1 plus the sacrificed artifact's mana value, put it onto the battlefield, then shuffle. Activate only as a sorcery.

Zabaz, the Glimmerwasp

Modular 1
If a modular triggered ability would put one or more +1/+1 counters on a creature you control, that many plus one +1/+1 counters are put on it instead.
{R}: Destroy target artifact you control.
{W}: Zabaz, the Glimmerwasp gains flying until end of turn.