Swatches - A fun and accurate color picker for the real world
EarMaster - Professional software for ear training and practical music theory on Windows and Mac.
ColorSnapper - The missing color picker for Mac.
Meludia - Listening exercises and to sharpen your ear and music theory skills
Sketch Palettes - Sketch plugin to save and load colors into the color picker
LenMus - LenMus is a free program for learning music.