Local restaurant telephone numbers, taxis, a card showing me the best local cell phone service to log into, numbers for the handling agents, embassy/consulate numbers, our company medical cover people, emergency credit card numbers, but not a list of knocking shops/massage parlours. All this stuff is on my I pad and in the address section of my filofax.
My predecessor discouraged carrying non-approved docs such as checklists/perf charts etc and after a chat with all the pilots they decided to carry on with that.