- https://www.gutenberg.org/
- https://openlibrary.org/
- https://www.planetebook.com/
- https://archive.org/
- https://www.smashwords.com/
- https://books.google.com/
- https://www.freetechbooks.com/
- https://www.getfreebooks.com/
- https://www.openculture.com/free_ebooks
- https://www.goodreads.com/
- https://www.oreilly.com/ (trial)
- https://annas-archive.org/
- https://pdfcoffee.com/
- https://singlelogin.re/
- https://www.ereaderiq.com/freebies/
- https://www.bookbub.com/ebook-deals/free-ebooks
- https://digilibraries.com/
- https://www.overdrive.com/
- https://manybooks.net/
there’s so many others and of course torrents