Flowkey - The easiest way to learn piano with your iPhone or iPad
Yousician - Learn to play music at home, at your own pace
Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.
Piano Lessons - Piano Lessons is one of the reliable libraries of online piano lessons provided by world-class instructors, making you learn or practice with the musical instrument without any hassle.
Synthesia - A fun way to learn how to play the piano.
HDpiano - HDpiano is the Netflix of Piano Tutorials.