There's this stuff called malunggay (moringa) leaf powder. It was one option recommended to me (the other option was domperidone) by Dr. Jack Newman for my low supply. I've been taking it and it *seems* to help (I can't be 100% sure though because I was taking fenugreek and Mother's Milk Tea and did some power pumping also).
The good thing about it is that it seems harmless and VERY nutritious anyway. You can try googling for some info.
If you do decide to try it, you most likely should go for the capsules. The powder tastes extremely YUCK to me