Sweet potato is really versatile as you say. I have had sewwt potato leaves stir fried, in hot-sour soup, with chilli dips, ... I have them growing (wild) in my veggie patch by themselves --no TLC ;-)

Taro is also good for food. Leaves are great too.

Yams (many varieties) are also low cared foos plants. They keep well as life plants until we need them.

These are high on the list of my self-sustainability plants.