It's amazing how a black on white or white on black fabric can jazz up a design. If I were you, I would take every fabric color I had and start laying it out as a sashing. Especially look for contrasts. Or take one of the blocks to Hobby Lobby or Joanne's and hold it up to every fabric they have that you think you may like. I've had to do that before when I just couldn't decide.
Or, look through this Bing search engine Crazy Quilt with Sashing images. Maybe you'll get some inspiration.
https://www.bing.com/images/search?q...ages&FORM=IGRE
Try a 3 part sashing....brown, teal, brown Sometimes that little bit of variance makes the difference.