It would be very nice to see a prototype or proof of concept of faceted search for Structured Data on Commons. Faceted search is a common design pattern on many websites, including prominent e-commerce ones, so it is certainly something the broad public is acquainted with.

The data model of Structured Data on Commons is flexible and under constant development - that's a given. Therefore, faceted search will also need to be flexible, i.e. not rely on fixed properties that will be present for every file, but rather preferably be responsive to the most-used properties that are present in a given set of search results.

A good source of inspiration is GraFa, a faceted browsing interface for Wikidata. With the example of the set of 'instance of sculpture' (i.e. all sculptures on Wikidata) as a starting point, this tool discovers that the most used properties are Creator, then Country, then Material used, etc.

• Compared to GraFa: for improved usability it would probably be extra nice if each 'facet' would already list the most commonly used values for that property as well.