[{"name":"bbb"},{"name":"ccc"}]

db.collection.aggregate([{$group:{_id:null,names:{"$addToSet":"$name"}}},{"$replaceRoot":{"newRoot":{results:{$filter:{input:["aaa","bbb","ccc"],as:"datum",cond:{$not:{"$setIsSubset":[["$$datum"],"$names"]}}}}}}}])