I have a couple of self made kits, one for the shooting range, and one for the house... at a minimum a couple of: pressure dressings (Israeli bandage if space is a premium, or Olaes bandage with occlusive side for chest puncture (they need to better control their vacuum sealing) a nasal pharyngeal airway and lube, a blood clotting gauze, chest seal/petroleum gauze if an Olaes bandage is not used, Kerlix gauze, and self adhering tape, gloves and shears... YMMV

most of my supplies came from Chinook Medical

https://www.chinookmed.com/