Yes horizontal nipples are great for rabbit but just use the stainless steel ones.@Molpet I have a spoiled rotten house floofer.
He doesn't count.
@Hope Hughes @RoosterML has a neat auto watering system for his quail cages. I think it might work for rabbits but it's a nipple system.
I use one of these:
https://www.chewy.com/frisco-wide-mouth-gravity-waterer/dp/335258
Trebbie has never knocked it over but I know/have heard that rabbits can knock waterers over easily.