I recently discovered https://www.datafari.com/en/index.html, it's more of an enterprise document management system, which is a whole new domain but I thought it would be interesting to link it with the idea of personal data management.
Such systems could be adapted for personal use.

On that, would you use or are you using such system? Probably your company is using one of these internally, but would you see yourself using that for personal docs, or with media in general. I know there's another whole branch for personal media stores/centers too. What about personal self-hosted search engines.