Colllor - With Colllor it is much easier to generate a consistent color palette with just a few clicks.
iWantHue - Colors for data scientists. Generate and refine palettes of optimally distinct colors.
Image Color Summarizer - The web service provides statistics describing color characteristics of an image identified by URL.
Palette Ninja - Create harmonious color schemes
Color Palette Generator - Enter the URL of an image and find its color palette
Adobe Color CC - Generates color themes that can inspire any project.