query: SELECT DISTINCT ?item ?itemLabel WHERE {
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
   
    # Item has a category that's main topic is a position (or a subclass of such).
    ?item wdt:P301/wdt:P31/wdt:P279* wd:Q4164871.
    
    # Item is not already marked as a set category.
    FILTER NOT EXISTS { ?item wdt:P31 wd:Q59542487 . } 
  }
  
  