Color Names, List of Colors: Name, CSS, RGB, HEX, HSL, Luminance. Let's you pick every single color by cmyk, rgb, color wheel etc, and see its name. Also let's you play with luminosity and hue, and gives all values of cmyk, rgb and color names.
Farnsworth-Munsell 100 HueColor Vision Test | How good is your colour vision? Do you have any defects in the range of colours that your eyes can distinguish? Do you suffer from some degree of colour blindness?