There are so many different manufacurers and colors, it is hard to get a good color chart.
Try this link, http://www.redrockthreads.com/mettler-thread/mettler-metrosene-thread.asp and you will find many color charts for many different makers.
Remember that colors vary on computer screens and the site may have some variables in their presentations of color charts. So, while not an exact science, that site will give you a very good idea of what you are looking for.
Ann has a lot of well priced thread sets and you might want to look at them for wonderful colors.
Pat
I hope you'll visit The Avid Embroiderer my blog for some tips and tricks from someone who enjoys sharing her discoveries.