Something like this just for photos has been in the back of my mind forever - it would be really nice to have a virtual folder built from images where the exif data says you used X camera or took the photos on X date. This would be useful for editing applications that are not catalog based, just point them at the virtual folder and query the images you want to edit, and there they are.
Edit - Someone mentioned befs but deleted their comment, it seems like it might sorta be supported in modern linux, possibly just read only though:
Edit - Someone mentioned befs but deleted their comment, it seems like it might sorta be supported in modern linux, possibly just read only though:
https://github.com/torvalds/linux/tree/master/fs/befs