Some of you might already know, but I just found out you can download audiobooks via Book lib connect and return them afterwards. I just tried it and it worked, but I don’t know if they will find out, so if you try, maybe use the usual privacy measures. Have fun.
There are both private trackers and indexers specifically for audiobooks. Find them. The biggest tracker for it has an application process, read the rules and you’ll get an invite. Usenet… I can’t even remember how I got an invite