HailPixel Color Picker is one of the easiest to use CSS color pickers I ever encountered. The color picking area is the whole screen and you choose the color by moving the cursor around : back and forth for Hue, up and down for Lightness and scrolling up and down for Saturation.
When you reach the desired color, you save it just by clicking and then you go on to the next color. You can do this basically endless. Each strip is saved and you can easily copy every strip’s HEX value.
Website : color.hailpixel.com