For my kits, I add:

Some kind of stimulant - caffeine gum, NoDoz, Trucker speed, etc.
Preparation H
Tampons
Feminine pads
Tea bags - two of them, and cloves
Ace wraps
various joint braces (ankle, knee)
Duct tape
Vet Wrap ( the clingy medical wrap)

When we made the FAKs for the two kids, I decided to go with the fanny pack as a container and found enough extra room to include necessity grooming items like a toothbrush, toothpaste, bar of soap, q-tips, and a pair of clippers. We also picked up a little 'travelling' size deodorant bar for each of the kids, but those things are still a giant waste of space.

antiperspirant can be used on the legs or other parts of the body that have a tendency to rub and chafe.

Yeah, being a bigger guy I added baby powder automatically to the big FAK. And A&D ointment for a vast assortment of rashes and skin irritations that could occur. I've found the generic Vitamin A & D stuff from Wally world works just as well.

I add the following to my kit:

Clove oil and Q-tips. This will numb up most dental problems in seconds.
A pair of quality flat and fine tip tweezers. Cheap tweezers that don't mate up are a waste of space.
Diphenhydramine 25mg tablets, available at Costco for under $5.00 for a bottle of 400. They last years beyond the stated date as do most drugs when properly stored.
Collyrium eye wash and an eye cup.
Nupercainal Hemorrhoid Ointment. This is fantastic for numbing the skin, i.e. small burns, stings, etc.

Was it Mike who had suggested that certain kinds of "adult ointments" have surprisingly long shelf lives and work well as numbing agents?

A quality LED headlamp. Not very unusual, but often overlooked. Nothing worse than trying to work on somebody (or yourself) in the dark.

Great suggestion. I'm finding that I'm liking the headlamps more and more for their convenience. Although, I think I'd probably stick one of the Eveready LED headlamps, like those from Wal-mart. I have a couple of them and they have worked fine over the years. Cheap enough to have several and put one in the FAK. I'd keep the higher quality Petzl I have with my main equipment (I would consider the one in the FAK would be a spare).

Of course, if you can afford to have a bunch of the nicer headlamps, then that would be nice, too.

Hmm, great minds think alike I guess, or maybe the items listed above are not that unusual.

I too have oil of cloves. I have a crummy pre-packaged dental emergency kit, better than nothing (temporary crown or filling replacement). I carry a small pair of tweezers with an attached pre-focused magnifying lens, for one hand operation, works well to extract tiny splinters, metal shavings, etc. I carry another small magnifier to get the big picture of a small item. Assorted pins for probing, ouch. Regular stainless bandage scissors, rather than EMT sheers, personal preference. "EMT gel", a bandage in a tube type product sold for use to treat wounds on animals, seems to work the same for human animals as well, ha. Vetrap was also listed by someone else above, I like it too. I also carry a regular elastic bandage, older knees occasional need wrapping. While not unusual, I carry lots of moleskin. I have a small key chain LED light in my kit at the moment, but like the headlamp idea, you just can not get enough light when digging out cactus spines etc, and having your hands free is a big plus. Since I always carry my headlamp anyway, I guess I am covered.

Uncle Bills Silver Gripper...
Possibly the finest pointy tip set of tweezers I have ever owned. And when we had the OE site up and running, was one of our best sellers.