While most Trump supporters will be content with waving their banners and screaming, we already know that some of them will go much further. I predict:
a) Widespread random acts of Trumper violence, including arson, assault, property damage, etc.
b) A few shootings/killings scattered across the nation
c) One large, horrific mass shooting
I can't even hazard a guess at what the casualty count will be. How can the police deal with the threat of Trump rioters and murderers? They're already having to guard ballot processing centers to keep Trumpers from breaking in, and some screaming Trumper nutjob interrupted a press briefing in Las Vegas. They'll only get less and less sane as the news of their hero's defeat sinks in.