OpenAudible - OpenAudible Project Page
Macsome Audiobook Converter - Convert Audible Audiobook to MP3 / AAC at up to 300x faster speed and id3 tags kept.
RoxyApps eBook Conversion Tool - Convert djvu, epub, fb2, lit, azw, lrf and other eBook files to txt, pdf, pdb, rtf and other formats
TunesKit AudioBook Converter - Best audiobook DRM removal solution for Windows to remove DRM from iTunes and Audible audiobooks.
TunesKit iBook Copy for Mac - Easily remove DRM protection from Apple iBooks and copy DRM protected iBooks to DRM free ePub files.
Voice - Convert texts to audio files easily... Write your text, click export.