What are some good alternatives?

I have long thought to add a book search to my semi-popular Gnod literature projects (https://www.gnooks.com and https://www.literature-map.com).

But I always thought everybody is only buying at Amazon anyhow. Interesting to see the closing of a book shop on the front page of HN.

If there is a list of interesting alternatives, I will add them to this new book search page:

https://www.gnod.com/search/books