Feed Your Microbiome With Fiber-Rich And Naturally Fermented Foods : The Salt : NPR: "Another big one comes from fruits and veggies, called Fructo-oligosaccharides. It's shorter than inulin and adding it to your diet has been shown to reduce markers of inflammation.
Galacto-oligosaccharides are another form of fiber found in milk, and are broken down in the colon.
I was really surprised to learn about resistant starch as another form of fiber. It comes from more simple carbohydrates that have been cooked and then cooled; think of cold potato or pasta salad."