Since I didn’t buy a second inner pan to go with my current rice cooker, I haven’t used it to make anything but rice for all the years I’ve had it. In return the inner pan, after 8 years (more or less) is immaculate. Please be warned that using a rice cooker for anything but white rice will degrade the inner coating.

Having said that. I kept my previous rice cooker and used it in tandem with my current one until I took it to Spain.

Most successful alternative use was amazake - the “keep warm” feature is extremely useful for developing cultures, such as koji in koji inoculated rice.
I used to make amazake for events such as Girls Day in March and bring it to the school to share with the kids there - about 60% liked it, more than expected.
Similar process using the “keep warm” feature would be good for shio-koji, a fantastic ingredient for enhancing foods.

ainternational mentioned eggs - if you cook a few vegetables and garlic in oil (in or out of the rice cooker) and then, once they’re in the rice cooker pour on beaten eggs and cook they make a great frittata type dish that you can slice and eat at room temperature for picnics or bento.

The old rice cooker I keep in Spain has become mostly a slow cooker. Add ingredients, press the “cook for x hours” button and then go off to the beach or mountain. Once we’re back and showered, lunch is ready. We have no A/C there so it’s great not having to stand over a stove. The inside pot is, alas, completely knackered. I can still make rice with it, but the Teflon has all gone and it sticks like crazy. Am better off making rice in a thick nabe pot (heat retention is excellent so it cuts down on fuel consumption which has to come up to the third floor in massive “bottles” - still the mid Showa era in our flat there)