I don't know any alternatives exactly the same as Goodreads, but I'd suggest these as being in a similar area:
http://openlibrary.org
Free open catalogue of every book ever published, also lends books online
https://inventaire.io
@inventaire
Site for cataloguing your book collection and lending it to others
https://libreture.com
@libreture
Storage for DRM-free ebooks
...and on a related topic, here are some alternatives to Amazon Books/Kindle etc:
https://switching.social/ethical-alternatives-to-amazon-and-goodreads/