Android client with OPDS or other means to download my audiobooks?

[Freakeao]

I have DRM-free audiobooks that I want to listen to on my android phone. Are there any clients with OPDS or other support to download the books seamlessly? Like Librevox or Libby can do from their sources.

Or are there external clients to download the books that will work well with audiobook players. OPDS clients, something else.

In the past I've used a subsonic client to download the files from my subsonic server to get them on the phone. But checking if there is some better/easier way to do it. I run a home linux server with all my files already on it.

Thanks.