It is possible only 2 thing that cause this. From my experience.
If it from the ceiling, it is the roof tile chip stone. When some strong wind blow, the chip stone from the tile will drop down to the ceiling and cause the sound. Sometime pretty big chip stone.
Another cause is the ghost. If it come from the wall. Specially wall between neighbor. But not a everyday,mnth/yrs even la. Have this experience after the dog howling in the middle of the night. Like marble drop sound. Probably from my neighbor who her pass away husband coming back. Forget to ask for 4D.
What is the weird sound, behind the wall or at ceiling