Shapeways - Shapeways - 3D Printing Service and Marketplace
3D Hubs - Airbnb for 3D printing
i.materialise - i.materialise is an online 3D printing service, community and marketplace.
Prototype Hubs - Prototype Hubs is an online service that provides professional 3D printing and CNC laser, plasma, and waterjet cutting services for on-demand production of prototypes, individual products, and mass production parts.
Zazzy - Design and sell your own 3D printed jewelry
trinckle - An online 3D printing service provider in Germany. With a software platform paramate.