ConceptKicker - Crowdfunded 3D printed art
Muglaunch.com - Design and sell print on demand products easily @ Muglaunch
Nicely Noted - Subscription service for beautiful greeting cards and stamps
3D Hubs - Airbnb for 3D printing
LetterNote - Fine Stationery, Art Prints, Accessories & Collectibles
Mockupify - Automate your print-on-demand product creation process