Yep - once you get beyond basic first aid gear, one of the next most advanced things I would get is a stretcher.
People don't have to be very injured before they are nonabulatory.
If you need to move an injured person or get an injured person in/out of vehicles, then a stretcher is pretty much essential.
If you are transporting a patient in a vehicle, then a stretcher makes it much safer (easier to immobilize them in a flat space of a suitable vehicle on a purpose built stretcher).
You can get mil surp stretchers - the best one is made by North American Rescue Products and is called a WALK (Warrior Aid Litter Kit).
They consist of a folding stretcher in a backpack - with lots of space for other first aid gear.
For some reason, I couldn't pull up the video. But having antibiotics, whether medical, herbal, or OTC, is high on my list. I've always got some antibiotic ointment in my cabinet, my work pack, my recreational pack, and my BOB..