immersionVR reader update - supports PDF, comics & audiobooks & many extra features
Project Gutenberg offers over 56,000 free eBooks: Choose free epub books to download. You will find the world's great literature here, especially older works for which copyright has expired.
BookBub features limited-time offers for the best free books in over twenty genres, from both top-tier publishers and critically-acclaimed independent authors.
Free eBooks at Kobo
Comic Book Plus, is the premier site to download Golden and Silver Age comic books - all copyright free.
The Internet Archive is a digital library with the stated mission of "universal access to all knowledge."
It provides free public access to collections of digitized materials, including nearly three million public-domain books and comics
Open Culture to download hundreds of free audio books, mostly classics, as MP3 files.