MockMagic - A free, easy-to-use device mockup generator
Mixkit - High-quality stock videos that are completely free.
Platforma for iOS - The ultimate wireframe kit for app prototyping
Stampede it! - Free audio & video assets for your design projects.
Smart Watch UI Kit - Helps smartwatch designers to design easily, 52 design
Music For Makers - Licensing good music has never been this easy.