The library I use every month: Z-library via Tor.
After free registering you may download up to 10 books daily.
I'm yet to encounter a book in English which is not there.
Access via Tor: http://bookszlibb74ugqojhzhg2a63w5i2atv5bqarulgczawnbmsb6s6qead.onion/
Access via other browsers: https://www.reddit.com/r/zlibrary/wiki/index/access/
Pay attention to the scam sites, there are a lot. The correct sites are listed by the link above.
If anyone suggest Discord - this is scam, z-library don't use it.