Database
[{"id":1,"marcadores":[{"k":"G","v":"00"},{"k":"1","v":"A"},]},{"id":2,"marcadores":[{"k":"1","v":"A"},]},{"id":3,"marcadores":[{"k":"G","v":"03"},{"k":"P","v":"55"},]}]
Query
db.collection.aggregate([{$match:{marcadores:{$elemMatch:{"k":"G","v":{$ne:"00"}}}}}])