Are there gray vegetables

I know of a blue potato. Blueberries can be used as vegetables, but their juice is more purple than blue. No, blueberries can not be used as vegetables. Blueberries in there natural state they have seeds. Seedless blueberries are genetically modified to have no seeds. This, of course, could trick people into believing that blueberries are naturally seedless, and therefore a vegetable.