Diapers - cuts, hoof wraps
Duct tape - wrapping hooves mostly but has a million uses
Vet wrap - the obvious
Habitane - cuts and scrapes is also anti fungal
Bag balm - for minor scrapes and cuts
Plug in heat pad
Needles
Syringes
Gauze
Saline
Eye ointment
Bute
Spare tetanus shot in the fridge
Bandages
Poultice
(Save the liner out of paper feed bags for brown paper)
Plastic bags for sweats
Liniment
Stethoscope
Thermometer
Notebook and pencil

Ummm that's what I can think of off the top of my head