Just Color Picker - Free portable colour picker and colour editor for web designers, photographers, graphic designers and digital artists. Supports Windows and macOS.
Flowkey - The easiest way to learn piano with your iPhone or iPad
Instant Eyedropper - Identifying the color code of an object on the screen is usually an involved, multistep process:...
Yousician - Learn to play music at home, at your own pace
gcolor2 - GTK+2 Color Selector
Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.