UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.
Open Peeps - A hand-drawn illustration library.
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Control Illustrations - 108 free flat illustrations with customizable characters
Moqups - The most stunning HTML5 app for creating resolution-independent SVG mockups, wireframes & interactive prototypes for your next project
Handsome Illustrations - Create unique illustrations for websites & applications.