stain brushes made from stock from stock.xchange [link]
and the Morguefile [link]
as well as my own stock.
Made in PS 7 so should work with that version and above.
There's a link on spiritsighs-stock's journal [link]
to the ABR viewer which you can use to extract the brush images if you don't use PS or have an older version.
Rules for using my brushes can be found here [link]