[W] Have space, but what to hoard? [X-Post from Datahoarders]

I have a NAS with more space than I think I can ever use. Looking for something interesting/useful to digitally collect. But what? And how? Currently have 1TB of my DVD isos and another few hundred GB of personal PC backups. Can't figure out what else to do. Suggestions?

(Legal content please! I know I can get 100TB of music/films, but I don't want to risk copyright infringement).