I manage relevant files by utilizing the pin to sidebar feature and sections, and really love the sidebar feature. At times there can be a lot of files there and many I don’t own, making it hard to always remember what file was for what. 
Would be cool and very handy if I could add little notes or comments to these files just for myself. Perhaps when hovering over the file in the sidebar (or the tab) and showing the preview thumbnail, it could show comments I have added to the file as well. This could really help add relevant info for myself to remember about different files.
(Or if not per user notes/description for files, perhaps there could be a description field per file like components have that would show when hovering on files. Related request for file level description here: Add Descriptions for individual files in the file browser - #2 by cupps)