Database tool

This is probably where the FrameMaker Project tool should have been the right answer. Only it is still not useful for this kind of thing.

Where the Imported By Reference object is just a normal file, there's no simple way to track where-used. Even the file system only knows that FM requested it, and not for what document.

A stewardship convention can be very helpful on this. In a shop I managed, the scheme already in place was: imported objects were all assigned the next available accession number when created (and the number, description, date & author were logged in a simple master text file that had a UI for the purpose). The files were the number.type, e.g. 12345.tif, 12345.txt, etc.

Documents that imported such objects were required to have a discrete, but visible copy of that number near the object on the page. This could also be done via invisible text if necessary (making it invisible, but searchable). Generated PDFs all ended up in a specific enterprise hierarchy.

If it were necessary to find all the documents that invoked a given object, a PDF search of the hierarchy would discover them (and a few random instances of the same number strings, to be sure). This scheme even works for Copy Into Document objects, which is generally unwise.

Like you want a list of all docs that contain a specific image or text inset being used? I don't think I've heard of anything like that.