If your browser supports CSS properly, then you might find this html color picker useful.
I got really tired of not being able to find a list of colors that included more than a few hundred colors, or a GUI color picker thing for Linux or some other unixy thing, so there I went ...
I made one a few years ago. http://stderr.net/cgi-bin/color.pl
And it has been most useful to me and a few friends.
Useful for selecting text and background colors I'm sure. :-) I needed something to help me choose colors for lists and such and found my "scales" easier to use.