Besides soy, can other types of beans be fermented? Besides soy beans, can other types of beans be fermented?
Yes, any bean can be fermented.  Black bean is common, for example, but you can certainly experiment.  This site might be a good starting point. They recommend rehydration, then cooking, prior to fermentation. They recommend using yogurt, a commercial starter culture, or a brine from lacto-fermented vegetables to get the process going.