POP (Prototyping on Paper) - POP helps you make interactive prototype with ease. If you can draw, you can design apps.
Airfoil - This software is from the Rogue Amoeba company, built to run on Mac and Windows platforms. It’s an audio-based software that allows the computers sound to play over a network device. Read more about Airfoil.
Invision - Prototyping and collaboration for design teams
AudioRelay - Listen to your PC audio, use your phone as a mic or stream audio from your phone
Marvel - Turn sketches, mockups and designs into web, iPhone, iOS, Android and Apple Watch app prototypes.
SoundWire - SoundWire does audio mirroring (audio cast). You can use any music player on your PC or laptop like Spotify, YouTube, or iTunes and stream low-latency live sound over WiFi directly to your Android device.