Has anyone ever compiled a complete list of NG Ephemera along with estimated value for each item?
Compiling a complete list of NG Ephemera would be a Herculean to impossible task. I have boxes and boxes of advertisement mailings alone. The lecture series goes back over a hundred years and NatGeo Live! in numerous locations worldwide adds thousands of items. I have a set of the Seattle NatGeo Live! programs and ticket stubs that take up two boxes.
The other problem is coming up with a value of NG Ephemera. They are thinly traded and frankly not that any people want them. I am in the baby boomer generation and the generations that follow me are not into collecting physical "stuff." I have three rooms full of NG items and a very, very understanding wife. None of my adult kids, nieces, and nephews are interested in my collection.
Anyway, that is my 2¢ worth.
Wow that is quite a collection that you have amassed! My ephemera are basically contained in 2 ring binders and span the years from 1911 - 1943. Most are supplemental advertising booklets of the time. I do have an interesting letter from 1914 signed by O.P. Austin Secretary of the NG Society which I will post for comment.