Metalcraft — Carapace Forger gets +2/+2 as long as you control three or more artifacts.
Keyword: Metalcraft
Auriok Edgewright
Metalcraft — Auriok Edgewright has double strike as long as you control three or more artifacts.
Screeching Silcaw
Flying
Metalcraft — Whenever Screeching Silcaw deals combat damage to a player, if you control three or more artifacts, that player mills four cards.
Ghalma’s Warden
Metalcraft — Ghalma’s Warden gets +2/+2 as long as you control three or more artifacts.
Bleak Coven Vampires
Metalcraft — When Bleak Coven Vampires enters the battlefield, if you control three or more artifacts, target player loses 4 life and you gain 4 life.