Adobe Color CC - Generates color themes that can inspire any project.
Swatches - A fun and accurate color picker for the real world
Colllor - With Colllor it is much easier to generate a consistent color palette with just a few clicks.
ColorSnapper - The missing color picker for Mac.
iWantHue - Colors for data scientists. Generate and refine palettes of optimally distinct colors.
Colordot for iOS - A color picker for humans.