Mixxx - The most powerful free DJ software in the world.
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
Guitarix - Guitarix is a simple Linux Rock Guitar Amplifier for https://alternativeto.
MuseScore.org - Create, play back and print beautiful sheet music with free and easy to use music notation software MuseScore. For Windows, Mac and Linux.
VirtualDJ - Virtual DJ Software - MP3 and Video mix software for DJs
Finale - Finale, the world standard for music notation software, lets you compose, arrange, notate, and print engraver-quality sheet music.