Not often, but sometimes an eBay seller will throw in an extra card or two into the envelope. I always love it when they do that.
Here's what I had ordered, a 2004 Roy Oswalt Diamond Kings Framed Silver, serial numbered to 100. I love the 2004 Diamond Kings, one of my favorite sets from the 2000s. The set is almost impossible to collect however. There are 83 parallel version of the base card. The parallels have different sorts of foil, frames, relics, autos and combinations of each of these. Here's a 1993 Ted Williams Juan Gonzalez card the seller threw in as a bonus. I only have a handful of this set but I like it. Most of the cards feature retired players and Hall of Famers. The Dawning of a New Age featured young current players. Gonzalez would hit 46 home runs in 1993 with a .310 average. At the time he certainly looked like part of a new age. Unfortunately that 'new age' may turn out to be the steroid age. Nevertheless, I collect Gonzalez and didn't have this card.
Here's the other card he threw in.
A 1992 Super Country Music Trading Card featuring the band Sawyer Brown. What am I supposed to do with this? These guys released 15 albums between 1985 and 2005. I am not a country music fan, but to each his own I always say. There are currently two buy it now auctions on eBay featuring this card. One for $4.00 the other for $4.97. There aren't too many 1992 baseball cards I can think of that I'd be willing to spend $4-5 on.