Well, I will mention the unmentionable. I have not seen it included in any of the FAKs, but a few weeks ago it would have been a welcomed addition to one of my hiking companion's kits.
Preparation H, or some form of hemorrhoid ointment. One in our group had to cut short his trip due to the issue.
It is most likely up to each individual to take care of thier own personal areas, but had one of us packed some type of ointment for this problem, we all would have had to put up with less [censored] and complaining and our friend would have been able to finish the hike with us.
No doubt a "free giveawy" when required, replace after each use.

Happy New Year!