Here's a promo that wasn't sent to dealers and it wasn't a giveaway at a show. It's the "Spider-Man: The Venom factor" card (Marvel Entertainment Group, Inc., 1994) which was available only as an insert with the first printing of the hardcover novel of the same name. It was enclosed in a plastic holder attached to the inside front cover of the novel.

Many collectors didn't know about it right away but by the time we did hear about it, the hardcover was in the bargain section of bookstores so you could get the book with the card for about five bucks. Even today, you can find it for around ten bucks.