I was doing some exhaustive research into Sandy Alomar Jr. cards and came across some mention of a previously unknown (to me anyway) variation in 1989 Topps that is apparently well-known enough to be mentioned in a number of places. Look here:
If not, I will point it out. Alomar's hat in the first card is significantly farther away from his hat in the second card. It is not a major variation, but it is apparently at least somewhat identifiable as many sites have it listed as a variation. So upon seeing this, I decided to take a look at the card that I had previously, which turned out to be the second card, then consult my doubles box (yes I have a box of doubles of Sandy Alomar Jr. specifically) to see if the first version was in there. Sure enough, it was. So I added a new card to my collection without having to check the mailbox.