Antifa ; Anonymous
I've met members of both.
Despite what everyone has read Antifa is a tiny closed-membership group, about ten to twenty members in the UK, probably the same in the US. They have one role which they stick to tightly, standing up to street-fighting fascists. They don't get involved in anything else. Didn't get involved in Occupy and I assume not these protests. Many young protesters called themselves 'antifa' because they assumed it was a cool contraction of anti-fascist, and Antifa were always livid about that and threatened them until they stopped. I told them I thought they were too protective about their name, but now the POTUS has labelled them a terrorist group I understand. But when a name gets co-opted, it's best to rebrand.
Anonymous started with a protest against Scientology which was cool. It's always reported that their Guy Fawkes masks were inspired by Alan Moore's 'V For Vendetta' I went up to them at the time and said, "V For Vendetta - cool!"
Sadly they hadn't heard of V For Vendetta, or Alan Moore, they were just the coolest looking masks in the nearest shop. Alan Moore was proud of the connection so nobody tell him. I'm sure they all got into him afterwards.
They published their 'Low Orbit Ion Cannon' attack plans, I forget against who, on an activist website, and me and another techie checked it out and went ballistic at them, and warned everyone not to participate. Ironically I guess it wasn't anonymous, it displayed your IP address. I recommended an HP stress test that did mask your IP but they knew better, and dozens of their volunteers were arrested. I thought at the time that was deliberate, to mask the one or two of them with botnets.