Gorgonzola: only solutions I found so far... we might have to create a page for each creature type, and then use DynamicPageList in each one to get a clean list of creature names, and then below have a manually maintained list of the main categories which can be formatted better. The only other solution is a "tree" extension which isn't installed.

Something like : http://wiki.guildwars2.com/wiki/Drake (the page about the creature type, is not the category itself)