With regards to epi-pens, I'd recommend that people with a history requiring one look into a holster option such as this* to keep it with them at all times, that way it can't get lost.

Pertaining to wilderness use, where rescue might take a while during an anaphylactic crisis and the initial dose wears off, the knowledge of this information* may prove useful - how to get several more doses out of a used epi-pen. Of course doing so is not medically recommended, some guesswork is involved in the dosing and you re-use a dirty needle, so it's a last resort only option.

Also, just a reminder as you compile your lists that allergies can occur with practically any drug, so having a backup option is wise. I'm severely allergic to diphenhydramine, which the active ingredient in Benadryl. I hadn't thought it was possible to be allergic to an antihistamine and so I kept taking it, despite my reactions, until a particularly bad situation that left no room for doubt (I had taken a prophylactic dose). With Benadryl out of the picture and multiple allergies it was a big, "now what?". Thankfully there are other antihistamines out there; Benadryl is popular because it's so good, but having an alternative plan is even better in my book.

Back on the first page someone brought up the potential need for strong pain meds in situations when nothing OTC would come anywhere close. There is a legal option that I feel obligated to mention but cannot in good conscience recommend: poppy seed tea. Sufficed to say people have died of morphine overdose from drinking it. Further details are easily found with a bit of research; again these are with normal poppy seeds completely legal and easily purchased. Not something I personally want anything to do with but a good thing to be aware of.

Also nice to know that eating something containing poppy seeds can cause you to fail a drug test...

*No affiliation