There were 30 riots declared by police in Portland alone between May and November (and many more since then). They have a detailed breakdown of riots, fires, projectiles thrown , arrests, ect.
This is probably the most popular example, but there's plenty of YouTube videos showing people popping up at places to tear down window barricades, smash them and run. They aren't there to protest. They're there to stir shit up and exploit human psychology.