Flowkey - The easiest way to learn piano with your iPhone or iPad
Text Case - Format any raw text on iOS and more 📝
Yousician - Learn to play music at home, at your own pace
EasyEmail - Gmail plug-in that helps you write emails quickly
Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.
Really Good Emails - A large collection of good product email design.