Duct tape,
foil blanket (they pack up so small, but bothy’s are good if out in sticks with groups)
dressing to absorb blood,
gloves (nicked from work)
I don’t carry a suture kit (even though I can suture) unless stuck out in S America, Africa etc (but then I carry a hell of a lot more).
Paracetamol (again unless in the developing countries)
All most people will need is some plasters, tape, dressing. There’s no need for splints, quick clot dressings etc. If you have to deal with catastrophic haemorrhage then I bet you’ll all be wearing or carrying something to use as a tourniquet.
It’s called First Aid not Critical Care. Don’t over think it (K.I.S.S) and remember that as said above, most of the first aid kit will degrade over time.
Be safe and use common sense.
A decent First Aid course is a good idea, but leave the serious stuff to the pro’s (we do deal with it regularly), just keep them alive until we get there.
Tom KP