I looked through the wiki and only found audio bay as a resource for audio books, which seemed limited. I'm mainly looking for non-fiction, especially of the "self help" and psychology variety. Books about dealing with mental illness or trauma to listen to while doing chores. Anxiously Attached is the main title I've been looking for, as an example.
Check if you have other library networks nearby. If you have city and county, might be 2 different library networks with more book selections. I have like 6 and some libraries even let you sign up remotely. I had a new York card for a month.
I have found most of the things I want through a combination of piratebay and 1337x for torrents, soulseek, librevox for old stuff and a library app. I have then mirrored what I have got via torrents up on to soulseek.
I have recently been using the scribd free trial so might be worth checking there, they do a 30 day free trial then when you go to cancel the sub they will offer an additional 30 days free too.