Seat of the Synod

Frogmite

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

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 artifact: Add one mana of any color.")

Banishing Knack

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

Steelfin Whale

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

Retraction Helix

Metallic Rebuke

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Counter target spell unless its controller pays {3}.

Springleaf Drum

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

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Mistvault Bridge

Mistvault Bridge enters tapped.
Indestructible
{T}: Add {U} or {B}.

Glaze Fiend

Flying
Whenever another artifact you control enters, Glaze Fiend gets +2/+2 until end of turn.

Thoughtcast

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