Site Palette - Get the essential colours from any website
Colour Contrast Analyser - TPGi's ADA Color Contrast Checker checks for helps determine the accessibility the contrast ratio of two colors for WCAG AA and AAA.
Color Palette Generator - Enter the URL of an image and find its color palette
Who Can Use - WhoCanUse is a tool that brings attention and understanding to how color contrast can affect different people with visual impairments.
Kontrast - Check and adjust web element contrast in real time.
EIII Checker Suite - The checker services can help you to locate and remove barriers on webpages or in PDF-documents.