I have been trying to document all the common tags for keys like amenity, shop, craft etc. in the Wiki using TagInfo. In the process I found several low usage tags that might have other matching well established tags. I put a small section with a Taginfo box and Overpass API link on those pages allowing mappers to find these tags in their area to fix them with local knowledge as some Tags might indeed be valid. Now I also added a category to them to make it easier to find all such tags in one's area!
Example how it looks on the page:
Would be great if everybody could take a look in his/her region and maybe clean up some outdated tags!