I like watching tack hauls, reviews, show clogs, and barn routine.
I always love watching “equestrians try... (sport, random other thing, anything really!)” I also enjoy watching videos of equestrians teaching non-equestrians to ride for the first time! If you are comfortable with someone riding your horse, it would be really interesting to watch someone who says horseback riding isn’t a sport ride a horse for the first time.
It could be anything you wanna share to the world really. How you became an equestrian, what exercises before riding that you prefer, what's in your riding bag, how to canter without stirrups, how to overcome the fear or riding again after a bad fall, vlogs about what happens during a riding practice of yours...
As for me I binge watch lots of videos on Youtube so you can find lots of ideas as well!