In order to check correct tagging of all parts of a road, this is a tool that creates a schematic view of any continuous road: Lane Visualizer. A detailed drawing of destination signs is included as well.
A list of keys that appeared in the database very recently: Latest Keys. Most of these are just typos and other mistakes.
A testing instance of Keepright - with some new checks and fixes that didn't make it to the offical web page yet.