Anyone know when 13.1 img be ready. Is it in the works?
I’m not sure.
I built a 13.1 version locally for my self based on the ‘master’ branch.
It required some manual changes to the package list. So I don’t think anyone is working on it right now.
(or it is done in some other branch)
I would also relay like to see a official 13.1 build. 
Hopefully very soon : FreeBSD 13.0 end-of-life