OpenAudible - OpenAudible Project Page
Apprentice Alf's DeDRM Tools - Everything you ever wanted to know about DRM and ebooks, but were afraid to ask.
DRmare Audio Converter - DRmare Audio Converter for Windows is a complete audio DRM removal tool designed to convert both protected audios, including Apple Music, Audible audiobooks, iTunes music, and common audios to MP3, WAC, FLAC, M4A, AAC, etc.
DRMBuster - DRMBuster is a powerful all-in-one audio and video conversion software for any kind of purchased or legally obtained music and video.
TunesKit Audible AA/AAX - Audible AA/AAX Converter by TunesKit is an application that enables you to convert audible AA and AAX files to the formats that are supported by other devices.
Sidify Music Converter - Sidify Music Converter for Spotify is a popular tool used to convert Spotify music to MP3/AAC/WAV/FLAC/AIFF/ALAC. It keeps original audio quality and ID3 tags after conversion.