In addition to my cards and cash I carry a spare R$50 note tucked away, a phone card, single edged razor blade, and I have a small tablet of paper that rides inside the fold that functions as my memory.  I also have a cut down pen refill in the fold so my memory never runs out of ink.
One thing I have started doing here in Brazil that I never did back in the States is to carry a magnetized razor blade in my shoe.  It is under the insole held in place with a piece of duct tape.  
This is kidnapping insurance.  Estrangeiros like me get kidnapped and tied up often enough that if it happens to me I will have the means to cut my bonds.  The magnetized blade also functions as a compass when suspended from a thread.  Thus may help to orient me as I would have arrived blindfolded or in the trunk of a car.
It is a slim chance this would ever happen but then again it is a slim blade in my shoe that is no bother at all.  Mac