NtEd - Music Score Notation editor.
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
music21 - Music21 is a Python-based toolkit for computer-aided musicology.
ABCexplorer - ABCexplorer is a musical creation utility that comes with advanced support to create, edit, play, convert and manage musical files with ABC text format support.
Canorus Music Score Editor - Canorus is a free cross-platform music score editor.
tonica fugata - Composing it for you... Automatic three and four-part composition (styles: J.S.