Good guess. Thunderbirds was a British adventure/sci-fi show from producer Gerry Anderson, using his (in?)famous "supermarionation" techniques (now on display in commercials for "Orbitz") and featuring lots of cool vehicles that ended up on toy shelves. Anderson later moved on to live-action fare like "Space:1999" and my personal fave, "UFO."
I know the cards were popular because a couple years ago they did a calendar featuring the original artwork. And at last report, a Thunderbirds remake was in the works with Jonathan (Star Trek: TNG) Frakes directing, so it might be a good time to sell this kind of thing.
Not sure if the Thunderbirds would show up in Hake's Guide, but it's worth a try. It at least meets what seems to be Hake's criteria: it was a case of toys being based on a show, instead of the other way around (like say, the Care Bears or GI Joe).
Original Thunderbirds website:
http://www.thunderbirdsonline.com/site/