One interesting thing has been to overdye wool from tweed jackets. You get a more dimensional color that way.
People who do rug hooking, like my sister, love to use these overdyed tweeds in their projects because they give subtle changes in shading. I use them in my projects to add a pattern to my solid colors. The sunflowers I made using some orange over-dyed tweed looks just fabulous!
Here are some examples of the colors of hand dyed wool I have been making in my kitchen. Using Wilton cake dyes and Vinegar, these strips of cream colored wool have been transformed into a rainbow of colors. I have found that the longer you keep the wool in the dye pot, the more vibrant the colors are.