Counterspell

Razortide Bridge

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

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}.

Novice Inspector

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

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.

Thoughtcast

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

Moonsnare Prototype

{T}, Tap an untapped artifact or creature you control: Add {C}.
Channel — {4}{U}, Discard Moonsnare Prototype: The owner of target nonland permanent puts it on their choice of the top or bottom of their library.

Gearseeker Serpent

This spell costs {1} less to cast for each artifact you control.
{5}{U}: Gearseeker Serpent can't be blocked this turn.

Ancient Den

Glint Hawk

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

Thraben Inspector

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

Plains

Leonin Elder

Whenever an artifact enters, you may gain 1 life.

Disruption Protocol

As an additional cost to cast this spell, tap an untapped artifact you control or pay {1}.
Counter target spell.

Seat of the Synod

Island

Candy Trail

When Candy Trail enters, scry 2.
{2}, {T}, Sacrifice Candy Trail: You gain 3 life and draw a card.

Lens Flare

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Lens Flare deals 5 damage to target attacking or blocking creature.