3D Vikings - 3D printing and fulfillment on demand.
Shapeways - Shapeways - 3D Printing Service and Marketplace
Avataaars - Mix and match avatars with a Sketch library
i.materialise - i.materialise is an online 3D printing service, community and marketplace.
Stratasys Direct Manufacturing - Custom 3D printing services.
3D Hubs - Airbnb for 3D printing