The first site I ever used for getting e-books was the-eye.eu's World Tracker Library. When the-eye went down and came back it looked like most of that section was gone, but just recently I discovered that there's still an enormous collection of links at https://the-eye.eu/public/Books/World%20Tracker%20Library/worldtracker.org/media/library/English%20Literature/sitemap.htm. However, actually trying to click on any of the links to download promptly results in me being blocked by one of my adblockers with the following message:
uBlock Origin has prevented the following page from loading:
Because of the following filter:
/jr.php?gz=$document Found in:
uBlock filters – Badware risks
Since it's an adblocker, though, I dunno how much of a risk there really is. I'd really like to be able to use these files as they're a lot more conveniently organized than the other sites I've been forced to use since the-eye originally died, but not at a risk to my computer.
Anna's archive is god tier for ebooks.
I used to download hard-to-find Windows ISOs from them but sadly they haven't reappeared last time I visited.
annas-archive is useful for looking for something in particular, but I don't like that there's no way to browse it.