Templates relating to grouping and categorizing all en.wikipedia categories.
Especially categories that would benefit from links to media (types, s.a. maps, images) the same or similar way it is done on Wikimedia Commons, in particular, and secondarily, other sister projects. Note: That all other language wikipedias and their sister projects tie into either the commons categories, or en.wikipedia's, or both with category interwiki's. At the same time, they tie main namespace pages (articles) to our en.wikipedia pages (articles) with interwiki's there, and similarly on wikibooks, wikisource, etc. Thus, the English language pages are common tie points for dozens of other pages.
This is one reason, among many, to keep as close a correspondence between en.wikipedia and the Commons category names as possible. In addition, the navigation links are very useful for locating related material on the other sister sites.