Documents by Readdle - A central hub for all your files.
Flowkey - The easiest way to learn piano with your iPhone or iPad
Documents Pro 7 - The ultimate all-in-one mobile office suite for the iPhone and iPad with 8 premium apps in 1.
Yousician - Learn to play music at home, at your own pace
GoodReader - With GoodReader on your iPhone, iPod Touch or iPad, you can read virtually anything, anywhere.
Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.