I always use this recipe,
https://www.baking-sense.com/2017/10/05/sourdough-donuts/ ,whenever I make SD donuts... I skip the cardamom though, and they're honestly to die for! I have also made a chocolate version, not my partners favorite, but they were pretty good! I believe I substituted half a cup of flour for half a cup of cocoa powder, it might have only been a fourth a cup though. They last for a couple days if you're willing to reheat them but are definitely the best fresh. They're also incredibly fun to make, this could be something good to do with the kids as long as an adult handles the frying part.
We also use sourdough for our pizza crust. It's literally as easy as pouring the sourdough starter directly onto a preheated cast iron skillet (coated with oil), spread it around with the back of a spoon (it'll be pretty sticky, be patient) add your toppings and then bake at 425 F for 8-10 minutes. I usually use between 180 and 200 grams of starter in our 10" skillet. I have used it just after it's peaked as well as when it's well into the "discard" zone. Very, very easy and delicious. Its our go to dinner when we don't feel like cooking anything else.