NtEd - Music Score Notation editor.

Stave'n'Tabs - iOS and macOS notation and tablature editor with MIDI and MusicXML files support and chromatic...

Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.

Tonelib JAM - Create, edit, print and listen to tablature and guitar sheet music

music21 - Music21 is a Python-based toolkit for computer-aided musicology.

Chordsheet Maker - Create chord sheets or lead sheets quick and easily from your iPad. Add rhythms, endings, segno, codas and all what's necessary for your musicians to know what's your music about. Transcription made easy!