I'd have to go back and look at mine but off the top of my head:

Soaking boot
epsom salts
iodine
diapers (get the right size for your horses foot/wrapping, but these can double for absorbing blood too).
Duct tape
vet wrap
banamine
bute
betadine
Gauze
oral syringe (one for giving oral medications/etc and one smaller syringe for cleaning out wounds/etc)
pill crusher
thermometer
Electrolytes
Leg wraps
Basic farrier tools (enough that you can pull a shoe if you needed too)
First aid scissors (blunt ends)

I also think it's a good idea to keep a list of ALL vets in the area, along with addresses of vet clinics. Yes you can google, but who wants to be worrying about that in an emergency. I usually make sure to get resting heart rate, temp, etc and keep it on a notecard somewhere as well. The last thing you want to do is take your horses temp and not be sure what normal is for your horse.