Re: Is there a way to make a smart collection of photos that are *NOT* currently placed in any collections?

I don't think so but you can do the following to find all photos NOT in a collection.

IN LIBRARY

Select ALL the collections.

Select all the photos    Menu  EDIT/SELECT ALL

Click on  "All Photographs"

Do   Menu   EDIT/INVERT SELECTION.

All the photos now selected are NOT in a collection.