Recently I introduced a few “OpenStreetMap Quality Control” categories:

• Fix Me - All map features which have a “fixme” (or similar) tag, categorized by suffix (e.g. fixme:name) or content (e.g. “name wrong”). It can also filtered by type of feature (e.g. Shop, Road, …).
• Culture - Media/Wikidata - In my opinion, each cultural map feature (artwork, memorial, tourist attraction, …) should have an image and/or a wikimedia_commons category (red=missing, light blue=set). Often, there even exists a Wikidata item (dark blue). Many memorials erroneously have the wikidata link to a person (magenta), this should most likely be a “subject:wikidata” (resp. “subject:wikipedia”) tag.
• Wikipedia - This category was in the “Special” top category before. It shows all map features in the area with a wikipedia or wikidata tag (including prefixes, e.g. “subject:wikipedia” or “name:etymology:wikidata”).