Icons-For-Free.com - Free icons sets, all sizes and popular formats, free licenses. Freebies icons sets
Xcode - Xcode is Apple’s powerful integrated development environment for creating great apps for Mac, iPhone, and iPad. Xcode 4 includes the Xcode IDE, instruments, iOS Simulator, and the latest Mac OS X and iOS SDKs.
Photo Lab AI Artist - Hand-drawn-quality portraits from selfies drawn by AI Artist
Angle 2 Mockups - A giant Sketch Library for creating app presentations
Flaticon - A database of free vector icons.
Balsamiq Mockups 3 - New public beta for the popular prototyping tool