I recently found the original poster that came with these stickers.
Turns out they are called CRAZY LICENSE PLATES, and I actually had this poster when I was a little kid.

The stickers were issued in loaves of Wonder Bread in 1976, and they all feature
Disney characters on "crazy" license plates from all 50 states.
The colors are accurate (within a year or so) of the proper colors for 1976 license plates.

One of the interesting things about the poster is that the states are listed in numerical order (Delaware to Hawaii)
rather than alphabetical order.