How about all those Donruss puzzle pieces from the 80s?
Ah, he beat me to it!
Ah yes. I loved putting those puzzles together as a kid and would like to collect all of them eventually.
Yes. The early 90's and I think donruss had late 80 ones as well.
I did a little research and Donruss did 15 different puzzles between 1982 - 1992 between different Donruss and Leaf products.
This topic would be a great side blog - you could have a post a day with the card you think best matches the theme and then others could weigh in.