The traditional word for those is "files" and traditionally the system for persisting files is called a "filesystem". Several of them are available; I typically use ext4fs and, for compatibility with the guy down the street who prints them out on paper for me, VFAT. Git can be helpful for synchronizing them between computers, keeping backups, and tracking changes in them, though you might want to use something like git-annex for large files like video. If you're not using Git, rsync and http are also effective ways of copying them around; tar or zip can streamline this sometimes.
With respect to terminology, I think you're counting those on the wrong side of the ledger; I think they're liabilities, not assets.