Black bloc is a well-established tactic where participants wear a simple, affordable uniform to make identification difficult for law enforcement. Wearers may extend it with basic safety gear in riot police are likely to be present with "less lethal" weapons. For example, motorcycle helmets, protective goggles, gloves.
One of the disadvantages of black bloc is it can visually alienate the protestors from non-participants. It becomes easier for mass media to frame them as scary outsiders, like professional criminals or terrorists, not regular members of society. Another issue is that basic safety gear is compatible but not implied, so having a uniform including this gear by default could make protestors safer.
I wonder if worker PPE is a viable alternative uniform. Is this an idea which has been tried? Surely I can't be the first to propose this. It's familiar, suggests the wearer has a vital worker role in society, and is capable of providing some level of protection by design. I'm not familiar with the different-but-similar yellow vest protests so I don't know whether there are any media optics vulnerabilities to be aware of or any other issue which came up there.