RapidComposer - MusicDevelopments RapidComposer: Music Prototyping and Automated Composition Software
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
Captain Chords - Write chord progressions in your favorite DAW
music21 - Music21 is a Python-based toolkit for computer-aided musicology.
Odesi - ODESI is a music sketchpad that exports your projects to Audio and MIDI.
Harmony Assistant - Harmony Assistant is an unbeatable software for computer-assisted music composition and editing.