
The cards feature the artwork of Dave Boss who did a series of NFL team paintings that were produced as the first set of team posters for the NFL back in 1965.
Note the infamous "CB" logo on the sides of the Browns helmets:
The following year, the paintings were featured on the covers of all the NFL team's 1966 programs.








Decks were produced for each team using the Dave Boss paintings:

I haven't found a picture of the Bears cards yet
Here is an picture showing the box the cards came in:




Since the Saints didn't join the NFL until 1967, presumably Dave Boss also did this painting for the Saints at a later date. Notice the very large fleur de lis on the helmet.


Still looking for the Cardinals as well
I'm glad Steve made me aware of these as I've always enjoyed the Dave Boss paintings as they capture the teams in a very colorful way, and showcase the teams' uniforms in all their mid 60's glory.
This series of cards was not Stancraft's first set of NFL playing cards as Stancraft had previously produced cards in 1963 with a red background featuring NFL logos and cards with a green background featuring helmets:


until the NFL later went with the no-strap look when using helmets to promote the league:

Stancraft later went back to the helmet design in the early 1970's with separate decks featuring the AFC and NFC (and of course no chin strap):

There have certainly been many other NFL playing card sets produced over the years, but I think the Stancraft cards featuring the Dave Boss paintings would have to rank as the best.