I bought a $30 off-the-shelf kit for both cars...one of which is my TV. I augmented the TV kit (due to camping) with a few items.
My list FWIW.
My personal favorite is that "new"
fabulous stretchy medical tape so popular in hospitals and labs these days. I also added a supply of superior band-aids and gauze pads. Then a set of REALLY good tweezers and an X-acto knife. A hotel sewing kit could do a few stitches. Finally a tourniquet is (sadly) an essential.
I keep a supply of alcohol wipes at home to refresh the kits. The ones in the kits dry out quickly (say 2 years).
In the console of my TV, I keep antihistamine spray and tablets, Tylenol and Advil, alcohol wipes and wet ones, hand sanitizer, and a couple of Cliff Bars. My adult son keeps an epi-pen in there, too. There are at least half a dozen bottles of water in the cab and in the bed tool box.
I also carry a space blanket and rain ponchos...all part of survival gear.
Speaking of tools, no emergency kit is complete without at least some tools. Lineman's pliers, hatchet, folding saw, nails, rope, and so on all contribute to being able to do things like splints, removing large thorns or splinters, or, in desperate times, being able to cut away fencing embedded in a wound. A tactical knife and several grades of flashlights are at my fingertips. There's also a tow strap, monster jumper cables, flares, glow sticks, and all that kind of stuff.
Our RAV-4 goes light on some of this stuff, but it, too, has rudimentary tools, a tow strap, jumper cables, several flashlights, a tactical knife, emergency clothes, and so on...all in an old gym duffel. But since the RAM has lots of storage, I take full advantage.
Other than a couple of band-aids, I've never needed the stuff for myself, but I've aided lots of people when camping, including at least a dozen jumps a year and plenty of wear and tear on the basic first aid kit.
Oh,
I almost forgot the large supply of fuses of all sizes. Again, never needed one myself, but the kit has saved several others' camping trips.
There's more than one kind of first aid. I'm into overkill.