Shade - Super easy color contrast insights and recommendations
Colorion - Curated color palettes with search and tags support
Contrast - A macOS app for quick access to WCAG color contrast ratios
Site Palette - Get the essential colours from any website
Color Contrast Cool - Tool to check color contrast as per in dev WCAG 3 APCA
Sketch Palettes - Sketch plugin to save and load colors into the color picker