There have been a number of significant football card sets throughout the 1960's and 70's that have been issued by food companies and various other manufacturers that normally didn't produce trading cards. In the hobby, we call those issues "non-standard."
Inserts are simply the extra "bonus" items featured in card packs that were not part of the regular issue set.
This section is a work-in-progress so not all the images below currently have links.