I am always interested when sovereign citizens are portrayed in fictionalized ways. In the Dec 5, 2021 episode of the TV show The Rookie, a man named Marvin Reynolds is a sovereign citizen plotting a terrorist attack, trying to kill as many people as possible. I did not watch it but it sounds like the police were able to prevent the attack.
You can read more here.
A real life case similar to this was that of Pepo Herd El who seemed to have been plotting a mass casualty attack but was arrested before anything bad could happen.
Another real case that came to mind was Andrew Joseph Stack III who flew a plane into an IRS building in Texas. That may have been less of a mass casualty attack and more a grand suicidal gesture.
The only other TV program involving sovereign citizens (that I am aware of) is season 6 of the show Bosch. The plot involved sovereign citizens attempting to bomb a courthouse.