Are there ever any "no smoking, pet-free" swaps?
 

Are there? (Not that I have anything against smokers or pets; just allergies)

Check the rules for each swap. With many of them the host will allow individuals to specify: smoke free, pet free, perfume free. If it doesn't specify, ask the host of the swap if they can accommodate you.

hosts cannot exclude smokers, pet owners, or those who like to use perfume, etc.
HOWEVER ... the rules do state that senders should be considerate of those who might have allergies; that things should be prewashed unless it's impractical; and that senders should have their submissions "sniff tested" by somebody else if appropriate.

it would probably not be practical to prewash commercially packaged strips, squares, etc.
but if we are swapping small pieces we cut from our own stash, i think the swapper absolutely should prewash at least once before starting to cut.

On the Secret Santa swap, we can specify if we have allergies, for instance to cigarette smoke. The hostess will then try to pair those folks with others, who don't smoke. If you ask the hostess of the particular swap, she/he may be willing to do the same. :)

partnered swaps are different in a few ways to "general" swaps.
hosts of partnered swaps are still not allowed to exclude people just because the have pets, wear perfume, smoke or have/do something that somebody, somewhere might not like.
but, since the host will be trying to make suitable matches otherwise, consideration of special needs is not inappropriate.

if it is not a partnered swap, be prepared to take what you get.
and make sure to bend over backward to make sure what you send is clean and odor free.

that's what washing machines are for.