Frogmite

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

Seat of the Synod

Retraction Helix

Until end of turn, target creature gains "{T}: Return target nonland permanent to its owner's hand."

Darksteel Citadel

Vault of Whispers

Steelfin Whale

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Whenever an artifact you control enters, untap this creature.

Springleaf Drum

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

Blood Fountain

When this artifact enters, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")
{3}{B}, {T}, Sacrifice this artifact: Return up to two target creature cards from your graveyard to your hand.

Myr Enforcer

Battered Golem

This creature doesn't untap during your untap step.
Whenever an artifact enters, you may untap this creature.

Mistvault Bridge

This land enters tapped.
Indestructible
{T}: Add {U} or {B}.

Etherium Sculptor

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

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Banishing Knack

Ichor Wellspring

When this artifact enters or is put into a graveyard from the battlefield, draw a card.

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.