Angle Finder™ - Angle Finder™, now rebranded to Protractor+, is an app that offers a handy protractor tool on your phone.
Tonelib JAM - Create, edit, print and listen to tablature and guitar sheet music
70 Degree : Smart Protractor - 70 Degree : Smart Protractor is an app that allows you to measure angles on the go with your iPhone or iPad.
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!
Clinometer + bubble level - Clinometer+ bubble level is a handy tool that measures angles and inclinations using your device’s camera.
Aria Maestosa - Aria Maestosa is an open-source (GPL) midi tracker/editor.