Black/pinto/kidney/garbanzo beans are great. Very low GI and very high fiber. It's up to you if you want to eat legumes. I think most beans are better than nuts. Some squashes like butternut work as well, though they're not all that starchy compared to a potato or rice.
The question is, why would you want starches that don't create an insulin spike? I eat a lot of starch for refeeds, but the whole point is the insulin spike, so I go for higher GI carbs. It's the low GI carbs I see little point in - you're taking in carbs and raising your blood sugar, but you're losing the beneficial insulin spike...not to mention the high GI carbs taste better - potatoes, rice, breads, etc. Why are you searching for a low GI carb source?
PS - the plan tonight is 2-4 99% lean ground turkey burgers and 2 pounds of white potato oven fries. Low fat, high carb and oh so good.
Don't put your trust in anyone on this forum, including me. You are the key to your own success.