I think there are other implementations, but they're proprietary so I didn't look into them very much. There are lots of posts out there about reversing virtualization obfuscation, but not many about implementing it. Seems like most people who put the effort into implementing it tend to prefer selling it commercially (which I suppose makes sense).
rusty-jsyc is the main open source implementation I've found, though it hasn't been touched in a few years: https://jwillbold.com/posts/obfuscation/2019-06-16-the-secre... (GitHub: https://github.com/jwillbold/rusty-jsyc)
I think there are other implementations, but they're proprietary so I didn't look into them very much. There are lots of posts out there about reversing virtualization obfuscation, but not many about implementing it. Seems like most people who put the effort into implementing it tend to prefer selling it commercially (which I suppose makes sense).