What brands/styles/types of protective gear do you like for activities that are dangerous?

https://www.helmet.beam.vt.edu/equestrian-helmet-ratings.html

This is a good place to start for helmets. They have the same sort of ratings for different sports so if nothing in the equestrian list looks good, you should check the bicycle list. Note that it's not necessarily current for everything but it's a good starting point.

Honestly the best thing is to learn how to fall without getting hurt. And how to bail safely if you lose control of the horse. That's some of the first things you should have been taught when you were learning to ride.

Best thing to do when falling is tuck and roll. Keep limbs from getting stepped on, get away from the horse, and prevent a hard landing.

Any OSHA approved ANSI level 4 or above cut and impact resistant stuff. Shit makes me feel like I'm in a suit of armor.

I'm on an extended hiatus from riding motorcycles, after getting sideswiped on the highway by an SUV. My minimal injuries and likely survival, I owe to my gear.

My criteria for selection started with looking at available standards for protective gear. In the case of motorcycle PPE, the EU generally has the best safety requirements, so, I'd generally select gear certified to the highest CE standards. My gear pieces were:

• HJC modular helmet (performed very well in independent studies). This saved my face, which I used as part of an unconventional breaking technique.
• Revit ADV-style jacket with CE level 2 armor inserts at joints and spine. This resulted in my only apparent external injury being a small abrasion on my arm, treated with ointment and a bandaid.
• Dainese short cuff gloves with CE Categoy II EN 13594 Level 2 rating (highest standard at the time). These literally saved my life. The steel sliders allowed me to halt my tumble and steer myself away from traffic.
• Motoport kevlar mesh overpants. Armor was upgraded as much as possible, exceeding CE standards and including coccyx protection.
• TCX Infinity boots rated at the highest CE standards at the time. These were heavily worn and near replacement. They did do their job well, resulting in only a sprain or hairline fracture of my ankle (suspect the latter with how much it bugs me these days). If I had been able to replace them with a new pair, my ankle may have been better protected.

Things that I think would have helped more:

• New boots
• Abdomen protection/armor (my worst injury was a minor hemorrhage of an adrenal gland from hitting my handlebars but needed no medical intervention).

For your case, I would recommend looking into dirt bike or ADV PPE. The sort of protection that you're looking for should be somewhat similar. An extra bonus is that you can likely wear body armor under your normal horseback gear (might need to size up). The technological advancements for impact armor this century are just amazing.

I allways keep a pair of Peltor Optime III ear defenders in my car in case I go planespotting at the airport.

I even keep a jar of extra earplugs if I am bringing friends who forgot their own ear defenders.

Planes a loud and I don't want my friends to risk hearing dammage.

Protect things you have 1 of the most. If a helmet has MIPS like cycling get it. You're unlikely to crash like me on a bicycle totaling SUV's, but with head/spinal injuries, every fraction of a second is critical. I was a very close fraction from dead in my major crash 10 years ago.

Magnum condoms.

I like them big. 💜

I bought a roll of bubble wrap for one of my sons. He wrapped himself up in it and his brothers helped him "test" the protection.

Strong against bludgeoning, but weak against slashing and piercing damage.

I didn't let them test any elemental damage.

I'm a wilderness hiker, climber, skydiver, and ride a motorcycle. I'd not ask another skydiver how to protect myself when climbing. They could guess. But, they'd know so little that their advice could easily be dangerous.

OP, ignore everyone who's not riding horses. Seek specialized guidance rather than general.

Might want to look into dirt bike protective gear. I am personally a fan of Leatt but there are loads of brands to choose from. I have never ridden a horse wearing dirt bike gear but I have hit the ground and trees many, many, times while dirt biking and it has served me well.

All of them. If something offers protection, might as well wear it.