Frogmite

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

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.)

Ornithopter

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.

Court Homunculus

Court Homunculus gets +1/+1 as long as you control another artifact.

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.)

Patchwork Automaton

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Whenever you cast an artifact spell, put a +1/+1 counter on Patchwork Automaton.

Myr Enforcer

Tempered Steel

Artifact creatures you control get +2/+2.

Icehide Golem

({S} can be paid with one mana from a snow source.)

Snow-Covered Plains

Cranial Plating

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

Steel Overseer

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