You can always mottle your own fabric. I buy many different colors of the Country Classic Solids at JoAnns when it is on sale, and then lay the piece of fabric in the bathtub, or outside on a sheet of plastic if it is too big, then I use a spray bottle with regular chlorine bleach in it and spray it. Some colors only require 30 seconds to get the desired color, some longer, then rinse completely with cold water and pop in the dryer.
I have a queen size quilt top done for my daughter which required lots of different colors, and did it that way, so even using the same base color, the shades came out different. This is the top just in the design stage, trying not to put any of the same colors together, still up on my design wall. Just need to quilt it now