Hmmm well unfortunately https://www.newgrounds.com/dump/item/03e5de635f219cdb34a8448d147a11b8
Might be that I have a too old version of the program though, couldn't find a way to add additional brushes at all - no need for PNGs. Saved for future use!
Cyberdevil
May be handy to have, thank you! Though I haven't used PS in a long time now, I wonder if they'll work with Fireworks also...
sincronikon
ABR's a super-simple format, so it might work! A quick Google suggests its possible. I don't mind exporting the shapes as PNG if it doesn't work for you, let me know!