you never know what may show up. Earlier this year (or late last year) a collection of NOS brochures showed up on eBay. Seller was helping to sell off stock that was in a building that housed a sewing repair shop. Machines were long gone, but a lot of smalller stuff was still there. Shop had closed back in the 50's and nothing had been done with it since.
So I got several new condition manuals from the 1920's -1940's