I can attest to the healing properties of yarrow that you mentioned. I once cut myself right by the crease of knuckle, always a tricky place to heal as any movement pulls the skin apart. Somewhat ironically it was whilst I was foraging - having borrowed a friends extremely sharp knife!! I chewed some yarrow and plantain leaves and put the green masticated pulp onto the cut, wrapped it around with strips of dock leaf (just because its long) to hold it in place. The deep cut stopped bleeding, and healed super quick. The yarrow is good for stemming blood and the plantain antimicrobial, both encourage healing. Both of these plants are very common and if out in nature at least one shouldn't be far away. I'd really encourage anyone to give it a try, if you do have a wound, I think its good to let it bleed a bit to clean itself. Then a good lick or splash with your water bottle, a foraged leaf poultice and you'll be good as new.

Definitely my kind of first aid!