I might use these colors in a water design of some sort. I love varigated thread, but have the same issue, where do I use it? This might also look good in a grassy design, after all, not all grass is green.
When I used these types of thread, I felt the colors became choppy and certainly followed the stitching format to a "T." I don't use them much, but do use them as one of several colors in the same palette.
I did find that I really liked using them in names and words, unless there is a lot of white or very light between the colors, depending on background color. If that is the case, it makes the lettering look odd and can be difficult to read.
I work at using colors that are very defined in relation to the background. A yellow to a dark color can be really outstanding. However, a yellow to a light color can disappear. One problem is denim, it can lose dark colors or light ones depending on the denim color. I once tried a black design on a dark denim and was less than pleased with the results.
Pat
I hope you'll visit The Avid Embroiderer my blog for some tips and tricks from someone who enjoys sharing her discoveries.