Swatches - A fun and accurate color picker for the real world
match.color.io - Automatically match colors of any image or movie with ML
ColorSnapper - The missing color picker for Mac.
Image Colour Transfer - A free-to-use browser-based application that allows an image to be recoloured to match the colours of another image using novel methods.
Sketch Palettes - Sketch plugin to save and load colors into the color picker
Color Palette Generator - Enter the URL of an image and find its color palette