Frogmite

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

Darksteel Juggernaut

Indestructible
Darksteel Juggernaut's power and toughness are each equal to the number of artifacts you control.
Darksteel Juggernaut attacks each combat if able.

Razortide Bridge

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

Thought Monitor

Affinity for artifacts
Flying
When Thought Monitor enters, draw two cards.

Memnite

Island

Swamp

Signal Pest

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Signal Pest can't be blocked except by creatures with flying or reach.

Oswald Fiddlebender

Magical Tinkering — {W}, {T}, Sacrifice an artifact: Search your library for an artifact card with mana value equal to 1 plus the sacrificed artifact's mana value, put it onto the battlefield, then shuffle. Activate only as a sorcery.

Mistvault Bridge

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

Somber Hoverguard

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

Darksteel Citadel

Springleaf Drum

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

Vault Skirge

({B/P} can be paid with either {B} or 2 life.)
Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Cranial Plating

Equipped creature gets +1/+0 for each artifact you control.
{B}{B}: Attach Cranial Plating to target creature you control.
Equip {1}

Assert Authority

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Nettlecyst

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each artifact and/or enchantment you control.
Equip {2}