Invision - Prototyping and collaboration for design teams
Mobbin - Latest mobile design patterns & elements library
Marvel - Turn sketches, mockups and designs into web, iPhone, iOS, Android and Apple Watch app prototypes.
pttrns - iPhone and iPad user interface patterns
UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.
Page Flows - User flow design inspiration for mobile & desktop