I personally use Tachiyomi or CDisplayEx if its on android. Or if it's on my iPad then I use the paperback app using repos, or for my own collection I LOVE YAC reader. The guy who develops it is super cool and actually listens to requests when they make sense and it's way better than Kavita or Komga IMO if you don't mind using your PC as a server.

Edit: typos

https://www.myanonamouse.net is a private torrent tracker for literature related uploads as well as audio books. It is a very friendly community and easy to join as long as you seed what you leech.