contrast-color
Determines the best contrast color to use. Give it a background color and it returns a foreground color (black or white by default but customizable).
font-color-contrast
JavaScript module to use black or white font according to the given background color
color-contrast-checker
This is an accessibility validator based on WCAG 2.0 standard for checking the color contrast.
wcag-contrast
evaluate the wcag color contrast score for two colors