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.)

Frogmite

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

Seat of the Synod

Ornithopter

Cranial Plating

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

Myr Enforcer

Steel Overseer

{T}: Put a +1/+1 counter on each artifact creature you control.

Springleaf Drum

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

Island

Thoughtcast

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

Phyrexian Walker

Darksteel Citadel

Arcbound Worker

Modular 1 (This creature enters with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

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.