There is no such thing as an allergy-free listing !
One also has to be completely clear about the difference between allergies and sensitivities. Someone could be hyper-sensitive to fragrances, while not actually being allergic to fragrances.
Also, degree matters. One person might be slightly allergic - maybe only getting hayfever symptoms like sneezing and watery eyes, while some people might suffer anaphylactic shock if exposed to certain foods such as shellfish or peanuts.
My sister was allergic to all kinds of things, and used to get asthma as a child, until she went for a course of desensitization treatments. Pollen, house dust (mites), certain foods, cats, dogs, feathers. When she went for the "pinprick" test, I think every one swelled up.
One can try to be hypo-allergenic i.e. try and limit potential allergy-causing agents.
But for most people with allergies, they will have specific things that trigger them. They have to be specific about asking in advance about their particular allergy or sensitivity.
e.g. Cats. I have cats, but I don't allow them into my guest space. If people are allergic, I usually tell them that, although the cats aren't allowed in the space, I do have central air, and there is the potential for dander to enter the space. Most people will then let me know if they will just take an antihistamine in advance, or cancel their request.