I thought I had heard of the knobbed celt/adz so I checked Hothem's Indian Axes and there is a photo of one from PA. It's odd looking. It looks like a reverse full groove axe. I have seen some grooves in the edges of large boulders at a couple of rock shelters in Kentucky that I thought might be shaft scrapers. Unfortunately the boulders were out in the weather and eroded so there was no way to tell for sure.

The one in the book is similar to the ones you posted. I couldn't tell from the photo in the book that it is only knobbed on the top and bottom. I thought there was a raised band around the entire tool. Knobs on the two smaller sides would work almost as well as a fully ridged piece and would take much less time to make. Interesting artifacts. Most of your shaft smoothers are obviously for that purpose where my two are more like sharpening stones, especially the one from Maryland. It looks like you racked on the recent finds. Congrats!