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.)

Myr Enforcer

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

Vapor Snag

Return target creature to its owner's hand. Its controller loses 1 life.

Vedalken Certarch

Metalcraft — {T}: Tap target artifact, creature, or land. Activate only if you control three or more artifacts.

Ichor Wellspring

When Ichor Wellspring enters the battlefield or is put into a graveyard from the battlefield, draw a card.

Mishra's Factory

{T}: Add {C}.
{1}: Mishra's Factory becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

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.

Thought Monitor

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

Cranial Plating

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

Emry, Lurker of the Loch

This spell costs {1} less to cast for each artifact you control.
When Emry, Lurker of the Loch enters the battlefield, mill four cards.
{T}: Choose target artifact card in your graveyard. You may cast that card this turn. (You still pay its costs. Timing rules still apply.)

Springleaf Drum

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

Darksteel Citadel

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Mistvault Bridge

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

Welding Jar

Sacrifice Welding Jar: Regenerate target artifact.

Frogmite

Ornithopter

Sojourner's Companion

Affinity for artifacts
Artifact landcycling {2} ({2}, Discard this card: Search your library for an artifact land card, reveal it, put it into your hand, then shuffle.)

Island

Thoughtcast

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

Ensoul Artifact

Enchant artifact
Enchanted artifact is a creature with base power and toughness 5/5 in addition to its other types.

Spell Pierce

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

Memnite

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}.

Tanglepool Bridge

Tanglepool Bridge enters the battlefield tapped.
Indestructible
{T}: Add {G} or {U}.