Keep vaccinations, as many as you can possibly imagine, that you think could be good for your operation/aircraft range up to date. I'm always amazed how many crew don't have vaccinations that are up to date.
Carry malaria tablets just in case you get flight to affected areas. If you regularly go to remote locations it's also a good idea to carry broad spectrum antibiotics.
I keep a private cash reserve of euro and US dollar, usually about 800-1000 of each. I always leave one credit card in hotel room or in aircraft when we have down time somewhere.
Carry some proof of emergency / travel / insurance, with contact details to an emergency hotline, in case you end up in an accident.
CP