Database
[{orderReceivedBy:"something",ID:150435,country:"UAE",createdAt:ISODate("2022-02-14T09:55:59.393+00:00")},{orderReceivedBy:"something",ID:150435,country:"IN",createdAt:ISODate("2022-02-14T09:55:59.393+00:00")},{orderReceivedBy:"something",ID:150435,country:"NL",createdAt:ISODate("2022-02-14T09:55:59.393+00:00")}]
Query
db.collection.aggregate([{"$group":{"_id":null,"countries":{"$addToSet":"$country"}}}])