Simply Piano - Fast and fun way to learn piano
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.
Yousician - Learn to play music at home, at your own pace
Guitartapp Chord Pro - Guitartapp Chord Pro is the world’s largest and popular music and audio app that allows you to throw away your songbooks and start jamming with this app.
Synthesia - A fun way to learn how to play the piano.