I keep 3 credit cards, drivers license, AAA Gold card, CCW card, Medicare and BCBS card, swmbo's sizes and my meds on the flip side of a piece of paper that I sealed in plastic. That's it. Actually that's all one needs. Keep the rest of any possibly needed stuff in a hidey hole in the vehicle to be used if needed.
I carry the stuff in a custom made calfskin card carry type wallet that has two compartments on either side. Very thin. I pick up a new one every couple of years from my leather guy, M.W. Barnes; mike@mwbarnes.com, and give the old ones to grandkids.