Self promotion, but I guess you’re specifically asking for it so I hope you’ll let it slide: https://github.com/saagarjha/VirtualApple. I’ve been using it for development so it’s “actively maintained” in the sense that if it breaks I’ll go fix it because I need it to work :P

Do note that the framework for Linux asks for a kernel+disk rather than an ISO. I don’t support it at the moment (the project is macOS-focused) but it wouldn’t be too hard to add support for.