Brushes to help draw worn, tattered edges, such as on old clothes or fraying fabric. I think they could be used to draw crumbling paper as well, like in an ancient book.
There are 4 types.
① Small / Slightly worn
② Moderate / Narrow rips
③ Big / Chunky holes
④ Fraying / Roughly woven
2, 3, 4 have a part that reflects the sub-colour, to help make overlapping easier. To remove it, make the sub-colour white and then use Edit → Convert brightness to opacity.
That is what I have done below. Then I tidied up the line art and coloured in the usual way.
Tatters