specific foods to consider if you want to break it down by prebiotics subtype::
GOS rich foods: lentils, chickpeas, green peas, lima beans, kidney beans.
FOS/inulin rich foods: onion, garlic, asparagus
XOS rich foods: bamboo shoots.
Also be aware that there is also benefit from the inclusion of prebiotic spices in diet such as black pepper, cayenne pepper, cinnamon, ginger, Mediterranean oregano, rosemary, and turmeric.
Note : prebiotic foods may be difficult to digest at first however soak, chop, steam to make easier to digest.