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.
ToneLib GFX - The perfect custom tone with a complete guitar studio in your computer
Yousician - Learn to play music at home, at your own pace
Rakarrack - Rakarrack is a richly featured multi-effects processor emulating a guitar effects pedalboard.