Razortide Bridge

Razortide Bridge enters the battlefield 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}.

Ornithopter

Blood Fountain

When Blood Fountain enters the battlefield, 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.

Frogmite

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

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Springleaf Drum

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

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Island

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Mistvault Bridge

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

Thoughtcast

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

Kenku Artificer

Homunculus Servant — When Kenku Artificer enters the battlefield, put three +1/+1 counters on up to one target noncreature artifact. That artifact becomes a 0/0 Homunculus artifact creature with flying.

Turn Aside

Counter target spell that targets a permanent you control.

Myr Enforcer

Steel Sabotage

Choose one —
• Counter target artifact spell.
• Return target artifact to its owner's hand.

Ancient Den

Reverse Engineer

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Draw three cards.

All That Glitters

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

Nihil Spellbomb

{T}, Sacrifice Nihil Spellbomb: Exile target player's graveyard.
When Nihil Spellbomb is put into a graveyard from the battlefield, you may pay {B}. If you do, draw a card.

Seat of the Synod

Thraben Inspector

When Thraben Inspector enters the battlefield, 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.