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.
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.
Palette For Mac - A menu bar based colour contrast analyser
Koa11y - Automatically detect accessibility (a11y) issues on webpages
Pikka - Pikka is a free color picker app for macOS designed to make the most powerful professional color editing tools accessible to everyone. With an extensive collection of tools, it's the only color picker you'll need.