Who Can Use - WhoCanUse is a tool that brings attention and understanding to how color contrast can affect different people with visual impairments.
Palette For Mac - A menu bar based colour contrast analyser
Cron Color - Free web tool for designing color palettes and checking contrasts.
Kontrast - Check and adjust web element contrast in real time.
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.