Darksteel Citadel

Myr Retriever

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

Blacksmith's Skill

Target permanent gains hexproof and indestructible until end of turn. If it's an artifact creature, it gets +2/+2 until end of turn.

Filigree Familiar

When Filigree Familiar enters, you gain 2 life.
When Filigree Familiar dies, draw a card.

War Report

You gain life equal to the number of creatures on the battlefield plus the number of artifacts on the battlefield.

Dispeller's Capsule

{2}{W}, {T}, Sacrifice Dispeller's Capsule: Destroy target artifact or enchantment.

Plains

Ancient Den

Court Homunculus

Court Homunculus gets +1/+1 as long as you control another artifact.

Crimson Acolyte

Protection from red
{W}: Target creature gains protection from red until end of turn.

Ghalma's Warden

Metalcraft — Ghalma's Warden gets +2/+2 as long as you control three or more artifacts.

Apostle's Blessing

({W/P} can be paid with either {W} or 2 life.)
Target artifact or creature you control gains protection from artifacts or from the color of your choice until end of turn.

Auriok Sunchaser

Metalcraft — As long as you control three or more artifacts, Auriok Sunchaser gets +2/+2 and has flying.

Lembas

When Lembas enters, scry 1, then draw a card.
{2}, {T}, Sacrifice Lembas: You gain 3 life.
When Lembas is put into a graveyard from the battlefield, its owner shuffles it into their library.

Basilica Skullbomb

{1}, Sacrifice Basilica Skullbomb: Draw a card.
{2}{W}, Sacrifice Basilica Skullbomb: Target creature you control gets +2/+2 and gains flying until end of turn. Draw a card. Activate only as a sorcery.

Mana Tithe

Counter target spell unless its controller pays {1}.

Ardent Recruit

Metalcraft — Ardent Recruit gets +2/+2 as long as you control three or more artifacts.

Mandible Justiciar

Lifelink
Whenever another artifact you control enters, Mandible Justiciar gets +1/+1 until end of turn.