Concept Library is website templates and layouts for Sketch or Photoshop.
The set contains 78 layouts and a style guide for each concept, for web-, interaction-, digital-, UI/UX designers, developers and marketers.
Angle 2 is a massive Sketch Library with over 500 devices, entirely in vector and completely customizable. Also includes a free Sketch Plugin for applying perspective mockups.
The Material Theme Editor helps you make your own branded symbol library and apply global style changes to color, shape, and typography. Currently available for Sketch, you can access the Material Theme Editor by downloading the Material Plugin.
Velvet UI Kit an allusion to the possibility to combine to create new work. Is high quality pack based on simple and clean design, includes 70+ iOS screen templates designed in Sketch, most popular categories (Sign In / Sign Up, Walkthroughs, Menu, E-commerce, Profile, Social, etc).