A few years ago a lucky #LaserDisc hunter bought a laserdisc that was used as a demonstration of the #EditDroid system that contained 30 minutes of unedited Return of the Jedi footage.
The footage has since been uploaded to YouTube as well and is a great example of modern lost media. There exists today film, media, and audio that may exist on LaserDisc or VHS but has never been remastered or re-released otherwise. Some folks go around hunting those down as a hobby.