Various utility holes and crevices
This brush set was initially designed to make acne scars, but they also look nice for many other uses (road, pavement, weathered effect).

The acne hole airbrush can be helpful for making a lot of indents at once. The crevice brushes offer more freedom.
With the crevice brushes, it’s best to work drawing a circle shape. You could try making the holes by circling from the inside to outside, or the other way around. Be warned, you may have to touch up the holes to make them look more even.
https://assets.clip-studio.com/en-us/detail?id=1790109 fur brush

Brush