Database
[{_id:ObjectId("314e0e088f183fb7e699d635"),name:"documentName",monthlyProd1:"Object1",monthlyProd2:"Object2",monthlyProd3:"Object3",}]
Query
db.collection.aggregate([{$set:{monthlyProd:{$objectToArray:"$$ROOT"}}},{$set:{monthlyProd:{$filter:{input:"$monthlyProd",cond:{$not:{$in:["$$this.k",["name","_id"]]}}}}}},{$project:{monthlyProd:"$monthlyProd.v"}}])