Color Palette Generator - Enter the URL of an image and find its color palette
Colormind.io - A color palette generator powered by deep learning.
Palette Ninja - Create harmonious color schemes
ColorTag - ColorTag is an API for color detection.
Adobe Color CC - Generates color themes that can inspire any project.
Colllor - With Colllor it is much easier to generate a consistent color palette with just a few clicks.