I guess I've been pretty lucky, in the fact that I've only needed a handful of the things on the list, and when I have, I've either had them in the house, or in the "cow box". We used to show cows for years, so it was stocked. But looking at the list, and doing a mental rundown of my barn, I really need to restock!
I use "Horseman's Dream" quite a bit, not only for the horses, but also on us humans, and the dogs...and even the cows! It's a veterinary cream with aloe vera, vitamins A, E, D & wheat germ oil in it. You can get it at any feed store, it comes in a blue & white jar. It can be used for cuts, scrapes, burns, chaffes...it's great!
As far as the banamine, I've used it a few years ago when my mare was savagly attacked & her leg was sliced open. It cut her pain down & she was able to stand for the daily shots & re-dressing of the leg. I really needed either that or bute yesterday when my oldest started his battle with (hopefully just) colic. When the vet was out today, we bought 2 tubes of bute from her. I don't know what prices are like where you are, but it was only $15 a tube here, and, in my opinion WELL worth it!!
I'm not a vet, but another "old cowboy" trick when you are caught short, too, is to have a bottle of Jack Daniels in the barn. When they start to colic, you can give them some of that - it is a relaxant, and will help them calm down. (When I told my vet about it, she was ok with it, didn't yell at me or tell me never to do that again, so please don't yell at me!!) This was originally told to me by an old cowboy who has been working with horses for over 50 years who learned from his father, and repeated by another working cowboy, too. It's not something to do all the time, but, in a pinch, it's better than letting the horse suffer, and it does work. Back in May, when my boy colicked, this is what we did, and it worked.
Another thing to have on hand is childrens Mylanta. This is from a vet-tech friend of mine, who is a horsey-girl, too. When they are beginning to colic, give them 2 ounces. This will help with the poop. (again, we told the vet today & she was fine with it)
Horses are God's apology for men.