Quoted from eli_lilly:Go to Google and use this format in the search field:
site:pinballcards.com mypinballmachine
-E
That is a good tip and seems to work for the majority of cards. But some, apparently, haven't been indexed yet and don't show up (i.e. Elvira).
Also, at the bottom of the Google search you'll a block of text about Relevant results. If you click the "repeat the search with the omitted results included." you'll see others in the set. For example if you search for Ghostbusters you get the V3 cards. When you click that link you get all the version.
Cheers!