I was talking with a relative who is an EMT. I asked them what thing I should have in my first aid kit that wouldn't be obvious to me (or that would not come in a typical store-bought first aid kit). Their answer was immediate: A tourniquet. "Everything else we can help with, but you have to stop the bleeding until we get there."
What are the less commonly discussed must-haves in your woodshop first-aid kit?