I think this was a set that GIMP never had! xtravaganceex3 made these not long ago and after our request allowed us to convert her set.
There are 9 brushes in a .zip pack.
Link to xtravaganceex3 DeviantArt page:[link]
Link to the original Deviation: [link]
PLEASE NOTICE THIS IS JUST A CONVERSION, CREDITS AND COMMENTS SHOULD GO TO THE OWNER!