Librivox appears to be part of, or associated with, archive.org, which is a great source in general.
If you go to archive.org and put in an author or title, it will show you all of the downloadable formats they have available - text, audio, video.
In my experience their search system is kind of clumsy, so if you don’t find what you want (assuming it is something that would be there in the first place, in the public domain, under Creative Commons license, etc.) - try searching in different ways.
Thanks for the tip...