Heartstone

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Slobad, Goblin Tinkerer

Sacrifice an artifact: Target artifact gains indestructible until end of turn.

Scuttling Doom Engine

Scuttling Doom Engine can't be blocked by creatures with power 2 or less.
When Scuttling Doom Engine dies, it deals 6 damage to target opponent or planeswalker.

Mirrorworks

Whenever another nontoken artifact you control enters, you may pay {2}. If you do, create a token that's a copy of that artifact.

Kurkesh, Onakke Ancient

Whenever you activate an ability of an artifact, if it isn't a mana ability, you may pay {R}. If you do, copy that ability. You may choose new targets for the copy.

Ruin Grinder

Menace
When Ruin Grinder dies, each player may discard their hand and draw seven cards.
Mountaincycling {2} ({2}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)

Iron Myr

Myr Retriever

When Myr Retriever dies, return another target artifact card from your graveyard to your hand.

Dreamstone Hedron

{T}: Add {C}{C}{C}.
{3}, {T}, Sacrifice Dreamstone Hedron: Draw three cards.

Mishra's Self-Replicator

Whenever you cast a historic spell, you may pay {1}. If you do, create a token that's a copy of Mishra's Self-Replicator. (Artifacts, legendaries, and Sagas are historic.)

Palladium Myr

Pia's Revolution

Whenever a nontoken artifact is put into your graveyard from the battlefield, return that card to your hand unless target opponent has Pia's Revolution deal 3 damage to them.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Myr Enforcer

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

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)

Sol Ring

Combustible Gearhulk

First strike
When Combustible Gearhulk enters, target opponent may have you draw three cards. If the player doesn't, you mill three cards, then Combustible Gearhulk deals damage to that player equal to the total mana value of those cards.

Hellkite Igniter

Flying, haste
{1}{R}: Hellkite Igniter gets +X/+0 until end of turn, where X is the number of artifacts you control.

Thran Dynamo

Bosh, Iron Golem

Trample
{3}{R}, Sacrifice an artifact: Bosh, Iron Golem deals damage equal to the sacrificed artifact's mana value to any target.

Foundry Inspector

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

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Ichor Wellspring

When Ichor Wellspring enters or is put into a graveyard from the battlefield, draw a card.

Junk Diver

Flying
When Junk Diver dies, return another target artifact card from your graveyard to your hand.

Metalwork Colossus

This spell costs {X} less to cast, where X is the total mana value of noncreature artifacts you control.
Sacrifice two artifacts: Return Metalwork Colossus from your graveyard to your hand.

Steel Hellkite

Flying
{2}: This creature gets +1/+0 until end of turn.
{X}: Destroy each nonland permanent with mana value X whose controller was dealt combat damage by this creature this turn. Activate only once each turn.

Meteor Golem

When this creature enters, destroy target nonland permanent an opponent controls.

Oxidda Golem

Affinity for Mountains (This spell costs {1} less to cast for each Mountain you control.)
Haste

Liquimetal Torque

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

Basalt Monolith

Basalt Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap Basalt Monolith.

Sandstone Oracle

Flying
When Sandstone Oracle enters, choose an opponent. If that player has more cards in hand than you, draw cards equal to the difference.