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

iHandy Carpenter - An handy carpenter tool kit right on your device! There are 5 tools in this Carpenter tool kit:

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

Pocket Ruler AR - Pocket Ruler AR is a pocket ruler app that lets you measure objects and distances with your phone.

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!

iLevel – Protractor & Level - iLevel – Protractor & Level, now named Measure Angles – Level, is one of the most precise and easy-to-use clinometer and leveling apps that allows you to quickly and easily measure angles, slopes, and distances.