I have a thin Fanny Pack that fits my wallet and cell. It fits close to my body and I can even wear it under my clothing at the waist or shoulder. I also had a set of Dog Tags made that have my Name DOB Wife's Phone and Insurance data...
I am old enough now to have a pertinent Medical History so my Dog Tags have a good amount on information packed into just a few lines of data. I have considered adding a small Thumb Drive to them but I'm not that brittle yet...