[Mr.FixIt]

The agitators will have markings to identify themselves to each other: armband, handkerchief in a pocket, certain color shoelaces, etc... They’ll probably also have a few guys acting as C2 nodes, hanging back and scouting, with headsets or radios to coordinate activities.

I was watching one of the CHUMP (Capitol Hil Urban Millinial Pu$$y) zone "peaceful protests" online over the summer. One of the CHUMPs had some kind of squeaky horn that he repeatedly honked. It was distinctive and loud. He didn't seem to be a direct antagonist in the violence, um, protest. I think Antifa used it as an audible signal to let others in the ranks know where the leader was or where a target was. Keep an ear open for that sort of thing also.

[Mr.FixIt]

Visual indicators of the enemy could be holes in eyebrows, noses, lips, “gauged” ear lobes, etc. but without the associated hardware in order to blend in better.