In this video I think it's demonstrated incredibly powerfully what importance needs to be placed upon anti-horse tools.
The horses do the bulk of the work in creating space that allows the police line to tighten the noose here. Without them they never would have controlled these crowds with people on multiple sides of them. They could not have maintained control.
There must be simply and effective methods to spook these horses without causing a danger to them. Something that could be deployed that would make the riders tell their superiors "we can't deploy because the horses would be spooked by x".
Anyway. What are other people's thoughts here? Obviously this protest was unprepared for a fight (although several police have been hospitalised). What could small groups of 1-5 have done in the wider engagement to make things go differently?
I wonder, could you do the crazy geometrical shapes on banners? Like "dazzle" camouflage, or some optical illusions? I'm not sure if being on a soft fabric like a banner would yield the same result.
Or on tarps, to combine with @Awoo 's tarp thoughts below?
Possibly the bomb proofing that horses should have gone through might have given them some resistance to things like fluttering banners.
But anything that would make distances hard to make out for a prey animal that doesn't have forward binocular vision. So if the banner patterns somehow worked with the surrounding landscape to make it look like a wide two lane road was barely one horse width wide might help to confuse the animal about how much space it has to work with.
Second but... any pattern on a banner that could be carried and then deployed on the ground to make a solid roadway look like there is a huge hole in instead might be worth the effort.