Subcategories:
Web Colors 
Displays colors and color values based on input of two color values and selected number number of midpoints. Fast, annoyance-free site.
http://www.meyerweb.com/eric/tools/color-blend/
2. ColorCombo
Color charts, sliders, pickers, and converters for any use.
http://www.colorcombo.com/
A web tool that generates a compatible color scheme given a choice of starting color.
http://www.colormatch.dk/