Perhaps some of this type of "stuff" could be in with the packaging scans/pics.
I have a couple cards that came in with action figures, like '90 XMen, and a few from Star Trek. The figures were pretty much destroyed long ago. A mention of what they came packed with should at the very least be in a note field, if the cards are listed, or will be listed here.
Also have a couple pennants that came in some blaster boxes of a UNC college cards, that was the only way to get them. I can see where some of this stuff is a very grey area. Dog-tags come to mind, that have cards and/or stickers packed with them in bags or packs.
"I believe there ought to be a constitutional amendment outlawing Astroturf and the designated hitter." - Crash Davis