@greyor LibraryThing? https://www.librarything.com Free up to 200 books. $10/year or $25/lifetime for unlimited. Doesn’t even require an email address to sign up. From their ‘about’ page: “What information do I need to give up? None. Setting up an account requires only a user name and a password. We do strongly encourage you to include your email address when you sign up—this is very helpful in case you ever forget your password. You can also edit your profile to make yours a "private" account.”