We think we only have one rule which is: "No one has to eat anything they don't want to eat" - we have a 24/7 shop 150m away so it's easy for people to get food they do want to eat.
But actually we do have a few more:
"No smoking" - I don't think that should need to be an explicit rule in 2024 (thank fuck) as everyone except the nastiest types (my aunt) knows that if a household is nonsmoking then 99% chance they won't want you smoking in it. The few remaining smokers/vapers usually offer to go outside and are not offended at being asked to go as far from house as possible (in the past some smokers would get huffy and offended even when knowing people got ill from it grrr).
"Please avoid bringing sesame and walnut things into the house" - we used to be OK as long as Kim didn't eat it, but had some incidents where we think one/both of these in the air from cooking or in other people's pre-prepared food seemed to making Kim wheeze a lot and have to take loads of inhaler so decided to up the rule as we like Kim breathing properly. I don't buy/eat hummus when Kim is home for this reason.
"Please don't bring a dog into the house, Kim is severely allergic" - my Guide Dog owning pals have happy dogsitting friends when they visit. My stepmum used to moan about this rule when they had a (badly trained) dog my stepsister lumbered them with.. It says a lot about dog owners I find when we explain Kim's allergy, the good ones are great, keep their dog away and are respectful, the people who are shitty about it always have awful and badly trained dogs... (Probably confirmation bias on my part too thobut)
We probably don't remember to ask people not to spray smelly stuff like perfume and lynx-type-deodorant in the house, it's fine if it's just once in the bathroom with windows open but can otherwise be a breathing challenge for both of us.
"Help yourself to menstrual products", we have a wee note where they're kept saying "help yourself if needed" but due to Covid haven't had visitors in ages anyway. Most people would ask or just use stuff, but sometimes people do feel uncomfortable or unsure so a label was printed cos label printer.
"Don't try and do washing up", we're picky about how we do it (so many people are bad at it) and rinse it (people leave soap on stuff) and it's easier for us to just do it (we'll redo it if other people did it). We're happy to advise what chores are helpful when people offer tho.
I try to remember to offer people drink/food regularly but I am also happy for people to ask for stuff. I know not everyone feels able to ask, especially after I hosted Romanians who don't understand "help yourself" at all, so I have a script. A disabled friend loves me cos I will just help myself and manage food so she doesn't stress about having to remember to ask. Food is always a sensitive one in general cos there's so many expectations and bag mental luggage people have round it. A bulimic friend has a house rule to clear away food and dirty plates as soon as eating has finished which I'm happy to do. I like washing up so I usually do that as well which I am told is helpful.