Invision - Prototyping and collaboration for design teams
UI Garage - Specific mobile and web design patterns for your inspiration
Marvel - Turn sketches, mockups and designs into web, iPhone, iOS, Android and Apple Watch app prototypes.
Muzli - UI/UX and Design Inspiration Chrome Extension
UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.
Design Hunt - Curated design inspiration for everyone