Seat of the Synod

Frogmite

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

All That Glitters

Enchant creature
Enchanted creature gets +1/+1 for each artifact and/or enchantment you control.

Myr Enforcer

Razortide Bridge

Razortide Bridge enters tapped.
Indestructible
{T}: Add {W} or {U}.

Ancient Den

Gingerbrute

Haste (This creature can attack and {T} as soon as it comes under your control.)
{1}: Gingerbrute can't be blocked this turn except by creatures with haste.
{2}, {T}, Sacrifice Gingerbrute: You gain 3 life.

Blood Fountain

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

Goldmire Bridge

Goldmire Bridge enters tapped.
Indestructible
{T}: Add {W} or {B}.

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}.

Vault of Whispers

Ornithopter

Thoughtcast

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

Springleaf Drum

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

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.")

Mistvault Bridge

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

Chromatic Star

{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.