query: SELECT ?label (SAMPLE(?item) AS ?item) (COUNT(?item) AS ?itemcount)
  WITH {
    SELECT DISTINCT ?item ?label WHERE {
      ?item wdt:P136 wd:Q2864737 .
      MINUS { ?item wdt:P921 [] } .
    ?item wdt:P31 wd:Q3305213 .  
    FILTER NOT EXISTS { ?item wdt:P31/wdt:P279* wd:Q1278452 } . 
    ?item rdfs:label ?label .
    }
  } AS %missingmainsubject
  WITH {
    SELECT DISTINCT ?label ?mainsubject (COUNT(CONCAT(LANG(?label),STR(?label), STR(?mainsubject))) AS ?count) (SAMPLE(?item2) AS ?item2) WHERE {
    ?item2 wdt:P31 wd:Q3305213 . 
    ?item2 wdt:P921 ?mainsubject .
    ?item2 wdt:P136 wd:Q2864737 .
    ?item2 rdfs:label ?label .
    FILTER NOT EXISTS { ?item2 wdt:P31/wdt:P279* wd:Q1278452 } . 
    } GROUP BY ?label ?mainsubject
  ORDER BY DESC(?count)
  } AS %mainsubjects
  WHERE {
    INCLUDE %missingmainsubject.
    MINUS { INCLUDE %mainsubjects. }
  } GROUP BY ?label
  ORDER BY DESC(?itemcount)
  LIMIT 2000