Buzzing rattle in door pillar

[traveller]

I have had similar in a Yaris hatchback and it appeared to be the seatbelt height adjuster. It was intermittent. Initially I thought it was the grab handle above the driver's door.
You need to be 100% sure it's coming from where you think though. Noises can be very deceptive in a car. In this instance I sold it on to someone else to find.
In a previous car I had a rattle which again seemed to come from the belt height adjuster, I was convinced, even going as far as removing "B" pillar trim to check. How wrong I was, it was coming from behind the rear door inner trim panel! A rear seat passenger pinpointed it for me.
As advised you might need to remove some trim to find it.