Flowkey - The easiest way to learn piano with your iPhone or iPad
Chordbase Lite - Chordbase Lite is a paperless solution for the gigging musicians to display lyrics and chords on mobile devices.
Yousician - Learn to play music at home, at your own pace
Guitarix - Guitarix is a simple Linux Rock Guitar Amplifier for https://alternativeto.
Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.
SongBook - SongBook is a music app that helps you to manage your song collections complete with lyrics and chords.