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You reminded me of the file manager Ranger, which is indeed for file browsing, though files and folders are also one possible model/paradigm for cataloging and categorizing just about anything. (In fact in many ways, computers and especially unices reward you for cataloging information using this paradigm)

https://en.m.wikipedia.org/wiki/Ranger_(file_manager)

came here looking for ranger and wasn't disappointed. i love it!

The only thing that comes to mind is Nelson's ZigZag, but to call it practical and usable in its current state (gzz), is already a stretch.

http://xanadu.com/zigzag/

Look for gzz

It's a super interesting structure, but I don't believe there is a friendly version of it out there somewhere.

Would tellico[0] ("a collection manager for KDE") work for you?

[0] http://tellico-project.org/

https://www.tagspaces.org/

You could model your data as a filesystem with FUSE and then use any file browser.