I picked up a set of Shell A-1 ad glass on a visit to Mike Slama`s shop. It was amazing seeing all the globe lenses and ad glass piled on the shelves. His web site, Vintage Gas Pump Supply
https://vintagegaspumpsupply.com/ lists A-1 and A-38 ad glass but does not show any. He does have them available. A-1 ad glass currently in stock is the Shell pictured, Flying A chicken wing, Sunset and clear. I think there is a couple more that are out of stock right now. If you are interested in any and try to call him directly it is best to text. He is very busy during the week. There was two big crates of cut glass and after commenting on them he said it was only about one week worth.