Don't forget the fun stuff.
One of the few things I've ever sent in a care package that got specific feedback was a miniature version of this, and it cost me only about a dollar so. I sent it to a bunch of UAV guys in Iraq and they told me they spent their days gleefully throwing it around the office and at each other.
Deployed aircraft carrier Sailor "Southern" explains:
You never know exactly what they are sending when you get a care package. For example I received one from my mother and she found some little wind up dollar store toy. It was a dog holding a bone that would walk a little bit and then flip. I don’t know why, but for the better part of 3 hours while waiting for jets eight grown men spent playing around with that. We tried to see how high it could jump, how far it would waddle on how many turns of the knob. Then when the jets hit the deck we got busy and I lost it someplace. No big worries but, I wonder when it comes time to offload if I will find it.
'Cause when your daily work has life and death implications, it helps to have time to be just a kid again...