Whenever this question comes up I see myanonamouse recommended as a private tracker.

I just wanted to throw in that there is also a tracker called abtorrents which hosts audiobooks and ebooks, though I believe most or all of them are english.

I cannot speak as to the selection between those two unfortunately.

MaM (myanonamouse) is like the library of Alexandria

I get mine from Soulseek. I can usually find what I’m looking for.

hoerbuch.us if you want German content.

On Usenet altHUB and abook.link.