Internet Archive: National Emergency Library
provides a collection of books that supports emergency remote teaching, research activities, independent scholarship, and intellectual stimulation while universities, schools, training centers, and libraries are closed.
Internet Archive: Open Library
is an open, editable library catalog, building towards a web page for every book ever published.
Z-Library
is one of the largest online libraries in the world that contains over 4,960,000 books and 77,100,000 articles, aiming to make literature accessible to everyone.
Project Gutenberg
is a library of over 60,000 free eBooks. Choose among free epub and Kindle eBooks, download them or read them online. You will find the world's great literature here, with focus on older works for which U.S. copyright has expired.
Standard Ebooks
is a volunteer driven, not-for-profit project that produces new editions of public domain ebooks that are lovingly formatted, open source, and free.