Workshop Assistant

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

Cathodion

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

{1}, {T}, Sacrifice Chromatic Star: Add one mana of any color.
When Chromatic Star is put into a graveyard from the battlefield, draw a card.

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

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