Colordot for iOS - A color picker for humans.
Just Color Picker - Free portable colour picker and colour editor for web designers, photographers, graphic designers and digital artists. Supports Windows and macOS.
ColorSnapper - The missing color picker for Mac.
delicolour - GUI application used to choose colours
Swatches - A fun and accurate color picker for the real world
ColorZilla - ColorZilla is an extension for Mozilla Firefox and the Mozilla Suite.