Design Principles - An open source repository of design principles and methods
Mockups Design - Mockups Design is the most leading web-based application that comes with a vast collection of creatively design mockups for all kinds of products and devices.
Colorbox.io - Create accessible color systems 🎨
Mr. Mockup - Mr.
Lottie by Airbnb - Easily add high-quality animation to any native app
Pixeden - Pixeden is an all-in-one premium design and web resources platform that provides high-quality graphic design templates and lots of other files.