http://libgen.io/ 4.1k
http://libgen.rs/ 1.2k
https://b-ok.org/ 3.3k
https://1lib.domains/ 399
https://forum.mobilism.org/index.php?sid=6e7ceb3ef56a5db1a65753e70439b15b 1.4k
https://booksc.org/ 1.8k
https://filechef.com 1.1k
http://audiobookbay.pl/ 1.9k
http://pdf-giant.com/ 1.3k
https://magazinelib.com/ 824
http://ebook3000.com/ 1.1k
http://magzus.com/ 634
https://ebook3000.biz/ 653
https://www.magzter.com/top-free-magazines 445
http://pdfmagazines.club/ 641
https://nulledpremium.com/ 856
https://read-any-book.com/ 810
http://ebookscart.com/ 525
https://epubdrive.com/ 813
https://hotaudiobooks.com/ 1.1k
https://ebookpdf.com/ 648
https://sci-hub.tw/ 398
https://www.gutenberg.org/wiki/Main_Pag 279 (Just use browse option and go though categories)
https://www.free-ebooks.net/ 518
https://manybooks.net/ 443
https://www.ibiblio.org/ 378
http://www.authorama.com/ 283
https://www.bartleby.com/ebook/ 207
http://www.bibliomania.com/ 287
http://www.readprint.com/ 264
http://www.ebookdirectory.com/ 369
https://www.getfreeebooks.com/ 454
https://www.bookyards.com/en/welcome 248
http://digital.library.upenn.edu/books/ 512
www.b-ok.org/ 313
www.ebook777.com 445
https://8freebooks.net/ 427
https://bookflare.org/ 402
https://dlfeb.com/ 252
http://gen.lib.rus.ec/ 439
http://www.allitebooks.org/ 371
https://www.wowebook.co/ 387
www.pdfdrive.net 451 (books are outdated little bit here)
http://mirknig.su/ 418 (Russian website for books)
https://uloz.to/d8fpAg2rwEcYh/large-book-collection 1.3k (Extensive collection)
Try them and make your day!