The Destiny and Destiny 2 soundtracks are some of the best parts to the games, they harken back to Bungie's days on Halo and set the tone in a way the storytelling never did. For the original Destiny, a composition organised by three composers was set to be released, but Bungie never published it, and it has since been assumed lost. Some fans have now found what appear to be final versions of the songs from the album, Music of the Spheres, and have released it online.
The album, by Michael Salvatori, Martin O'Donnell, and Paul McCartney (yes, that Paul McCartney), contains nine songs, each linked to a planet/celestial body (or The Traveler) featured in Destiny. It has been released through the subreddit /r/DestinyTheGame, with user OS_Epsilon publishing it thanks to help from Tlohtzin Espinosa.
The post has two links to download the album, through Mega and a Google Drive, plus a link to a Soundcloud account that's hosting the album. Given this is not officially endorsed by Bungie, it's unclear if Bungie will be making steps to take the content down, although OS_Epsilon says to "share it at your own risk."
Jason Schreier at Kotaku claims that part of the reason Music of the Spheres was never released was because O'Donnell was fired by Bungie, but someone who had been given a copy shared it with OS_Epsilon and Tlohtzin to be published online. It seems that O'Donnell is quite happy about the situation though - it's certainly a unique Christmas gift.
— Marty O'Donnell (@MartyTheElder) December 25, 2017