Ecosyste.ms: Packages

An open API service providing package, version and dependency metadata of many open source software ecosystems and registries.

rubygems.org "books" keyword

bookshark 1.0.7
Extracts book, author, publisher and category metadata from biblionet.gr.
14 versions - Latest release: almost 4 years ago - 3 dependent repositories - 29.7 thousand downloads total - 9 stars on GitHub - 1 maintainer
kindle-highlights 2.0.1
Until there is a Kindle API, this will suffice.
11 versions - Latest release: over 6 years ago - 5 dependent repositories - 31.7 thousand downloads total - 567 stars on GitHub - 1 maintainer