Sure, although you'll need to experiment and I cannot assure you it will work. Sometimes crushed garlic interferes with the yeast and the loaf doesn't rise as high, and sometimes adding cheese adds moisture and keeps the loaf a little wet. You can definitely add herbs and spices such as rosemary or an Italian herb blend. I don't have a recipe for any add-ins, but you should check the comments because some people have left tips there.