There's also vioGSF (if I'm remembering the name correctly). I don't remember what codebase it's based on, but I seem to recall some people prefer it over Highly Advanced. Hopefully someone will provide a link, as I don't have one for it (try a search on this forum for vioGSF, or maybe even a Google search).
As far as I know, there's only 2 GSF players. Highly advanced, and vioGSF. If there's others, I haven't heard of them. Hopefully vioGSF is what you're looking for because if it isn't, you're out of luck (as far as I know). Mouser X over and out.