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.
Visily - The easiest and most powerful wireframe software for agile teams.
Angle 2 Mockups - A giant Sketch Library for creating app presentations
PSD to Sketch Design Converter - Convert a Photoshop design to a layered Sketch file for free
Balsamiq Mockups 3 - New public beta for the popular prototyping tool
Zeplin - Collaboration app for UI designers & frontend developers