Sist2 (Lightning-fast file system indexer and search tool). I’m not suggesting this is most unique use case, but noone mentioned it. I was mind blown when I became aware of it. I was looking for a way to manage my digital book and document archive for a long time. Tried various book management solution but none had full text search across whole library. Its lighting fast (like instant) you get excerpts with thumbnails and links to the files. Point it to your storage and you will gain extremely efficient way to look at your archives and references. Btw. I was already well organized and structured with my files, but going through it and searching for things I knew were there, was always a bit of a pain.