Pumpkin, rutabaga, winter squash, sweet potato, celery root (celriac), brown rice, blue potatoes, barley, steel cut oats, whole wheat flour, whole wheat pasta, these will all work to thicken your soups or sauces. The veggies can be run through your blender to make them silky smooth before adding them to the soup. Another diabetic freindly thickener is silken tofu. Egg yolks will add body to soups, as will collagen containing tissue, such as cartilage, and connective tissue.
Hope that helps.
Seeeeeya; Chief Longwind of the North