Ancient Den

Glint Hawk

Flying
When Glint Hawk enters, sacrifice it unless you return an artifact you control to its owner's hand.

Shield Sphere

Defender
Whenever Shield Sphere blocks, put a -0/-1 counter on it.

Leonin Elder

Whenever an artifact enters, you may gain 1 life.

Ornithopter

Court Homunculus

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

Ethereal Haze

Prevent all damage that would be dealt by creatures this turn.

Obsidian Acolyte

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

Galvanic Blast

Galvanic Blast deals 2 damage to any target.
Metalcraft — Galvanic Blast deals 4 damage instead if you control three or more artifacts.

Ardent Recruit

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

Oblivion Ring

When Oblivion Ring enters, exile another target nonland permanent.
When Oblivion Ring leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Frogmite

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

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Myr Enforcer

Kor Skyfisher

Flying
When Kor Skyfisher enters, return a permanent you control to its owner's hand.

Great Furnace

Vault Skirge

({B/P} can be paid with either {B} or 2 life.)
Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Auriok Sunchaser

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

Tooth of Chiss-Goria

Flash
Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
{T}: Target creature gets +1/+0 until end of turn.

Plains

Celestial Flare

Target player sacrifices an attacking or blocking creature of their choice.

Battle Screech

Create two 1/1 white Bird creature tokens with flying.
Flashback—Tap three untapped white creatures you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Unmake

Bonesplitter

Fragmentize

Destroy target artifact or enchantment with mana value 4 or less.

Thraben Inspector

When Thraben Inspector enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")