BaGLAMa
BaGLAMa 2 is a tool by Magnus Manske which lists some important Wikimedia Commons categories (mainly from partnerships), the Wikimedia articles which use their contents and the pageviews thereof. Since 2020, it is possible for anyone to add Commons categories to the tool; please use common sense when doing this, as very large categories or category trees are difficult to process.
Until 2015, it's been the only source of data for cultural institutions to see the impact of their work with Wikimedia, see for instance Europeana/Stats.