Leftist Theory Audiobooks - Leftist texts hosted on Youtube
Raddle's Audiobook Library - (Under construction)
Loyal books - 7000+ audiobooks
OpenCulture - 900 audiobooks
Lit2Go - Literature classics from a university library
French: http://www.litteratureaudio.com/ - 6000+ audiobooks
Piracy (use privacy software or vpn)
Audiobook Bay - huge selection
Unwelcome Guests Audiobooks - a few direct MP3 downloads
Android: Voice (Audiobook Player) - Great interface and features, and of course free/GPL software.
iOS: Audiobook-Player/BookPlayer - free/GPL software
If anyone has additional sources/software to list, I will add them. Thanks.