I have not seen it mentioned, but two items I have included in my first aid kits are a finger nail clipper and an eyeglass repair kit.
The finger nail clipper is a God send when needed, a knife just doesn't work on a hangnail and can make matters worse.
A $2 eyeglass repair kit from the drug store, self contained in a plastic tube, has helped others in my party more than once.
They are both small items, inexpensive and perhaps extravagant, but they do come in handy.