It turns out that the cautionary tale from my previous post, Caveat eBay Chess Autographs, is not unusual. While researching the matter I encountered many statements like 'over 80% of autographs on eBay are fake'. There is plenty of advice on how to avoid fakes. Here are two from the same eBay seller:-
Chess autograph collectors have the additional resource that I mentioned in the 'Caveat' post: Chessautographs.com. Here's an example of the sort of info found on the site.
That display is split into three parts. First there's a list of the players shown on the item; it can be sorted in different ways by clicking on the column headers. Then there's an image list of the individual autographs on the item. Then there's the item itself.
All of this can be accessed top-down in different ways: by autographed item, by player, or by annual rating list. Want to find the Bobby Fischer autographs? Click 'Chessplayers', click 'Fischer', and voila! The five Fischer autographs currently in the collection are shown along with Fischer's Wikipedia page (or change that to get his Chessgames.com page). I wish I'd had that resource when I bought the eBay item that had all the players' signatures in the 1979 Riga Interzonal except the one I was most interested in: Mikhail Tal's.