Someone suggested this to me a couple weeks ago. I JUST started playing with it, so I'm not sure if it would work for you or not:
http://links.giveawayoftheday.com/datacrow.net/
Also,
https://www.collectorz.com/book looks really cool. But it is NOT free. I really like the way it looks.
I have come very close to buying it a few times.
I really wish there were a way to install Calibre twice, one named Calibre, one named Calibre Audio. Yes, I know I can have all kinds of different virtual libraries within Calibre. That just doesn't work for me, I need two separate programs. Yes, I'm weird!
S