Sol Ring

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Imotekh the Stormlord

Phaeron — Whenever one or more artifact cards leave your graveyard, create two 2/2 black Necron Warrior artifact creature tokens.
Grand Strategist — At the beginning of combat on your turn, another target artifact creature you control gets +2/+2 and gains menace until end of turn.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Workshop Assistant

When Workshop Assistant dies, return another target artifact card from your graveyard to your hand.

Ashnod's Altar

Foundry Inspector

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

Nim Deathmantle

Equipped creature gets +2/+2, has intimidate, and is a black Zombie. (A creature with intimidate can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a nontoken creature is put into your graveyard from the battlefield, you may pay {4}. If you do, return that card to the battlefield and attach Nim Deathmantle to it.
Equip {4}

Krark-Clan Ironworks

Junk Diver

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

Myr Retriever

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

Cloud Key

As Cloud Key enters, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Resurrection Orb

Equipped creature has lifelink.
Whenever equipped creature dies, return that card to the battlefield under its owner's control at the beginning of the next end step.
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Tortured Existence

{B}, Discard a creature card: Return target creature card from your graveyard to your hand.

Sensei's Divining Top

{1}: Look at the top three cards of your library, then put them back in any order.
{T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

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.

Sculpting Steel

You may have Sculpting Steel enter as a copy of any artifact on the battlefield.