LilyPond sheet music text editor
audio sequencer
Featureful native Commodore 64 music tracker with MIDI/XM converter
Massive audio tagger
Open source brainwave entrainment application
TED-chip music editor for Commodore Plus4, Commodore16 (and C64)
Free and Open Source Brainwave Entrainment application
Music Manager focusing on ID3 tags and internal player
Guitar helper for old computers: scales, chords, and much more