No. 6 Raw Oysters
You don't see this very often, but every once in a while, especially at the fancier catered tailgates. Pick up a sack and a couple of oyster knives and just go to town. Football season is comprised mostly of months that end in -R anyway.
No. 11 Sausage Balls
Combine loose sausage, cheese, make into balls and bake. Honestly that's pretty tough to beat. This is another thing you'll see at tailgates around the country. This works incredibly well for a morning breakfast tailgate for those unfortunate afternoon/noon kickoffs as well. Some deli/catering places can really add some different varieties here.