A talented man named Tim Proby created sigils inspired by Game Of Thrones for every NFL team, and some of them are damn good. Even the Jaguars came across as intimidating with one of Proby's designs. House Gabbert will reign in the AFC South! (OK, not really.)
NFL sigils would be a hit at tailgates, although horses probably aren't allowed in the parking lot. A fan would have to find another way to ride proudly with his team colors waving in the wind.