It seems to be rather well known that armed forces have used playing cards to help soldiers learn to identify naval and aircraft. (I hope to collect more myself.)
In more recent years, playing cards have been used for another special purpose: Historic preservation.
I was lucky to find one such former government-issue deck. This one is specific to Afghanistan and I know Iraq ones exist as well. Cards inform soldiers to avoid buying antiquities, prevent the destruction of archaeologically significant sites, protect museums, leave important items in situ for later study, etc.
I will attach a few photos here. I apologize for their poor quality. (They were done a while ago and quickly.) I can re-snap. Just let me know.