Trust me! It probably doesn't matter WHAT is in the box- just that a box arrives!
Do you have a boy or a girl? These are things we did for our daughter.
Silly things were received well. For the holidays, go to the dollar spot at target. Green beads and green over sized plastic glasses for st Patrick's day etc. plastic bugs and creepy stuff for Halloween. Kid tattoos. Stuff to hang on the door. Penny candy - to share with friends.snacks. Dollar bills.
Another fun thing that was well received was mail from pretend famous people. Valentine cards from the latest heart throb etc. just print the picture from the internet, write something funny and mail.
Funny holiday underwear. Funny socks. Packet of cocoa or tea bags. Book of stamps. Water balloons. Wendys gift cert for a frosty ( a book of 20 - they had them for Halloween) ring pops. Suckers.
I went to the PO and got ten of the flat rate smaller boxes. I went home and addressed them all. Decorated them with sharpies on the outside. Put a sticky note on them FALL, WINTER, SPRING, HALLOWEEN, VALENTINES, etc as I found or thought of things, I put them in the box. Cut funny stories or jokes out of paper/ magazines. Printed pictures from her childhood ( Halloween costume for the Halloween box etc) bough a bag of tootsie roll pops. Put orange ones in Halloween box, red in valentine box etc.that gave me a head start on getting the boxes ready to mail.
One thing she commented on. Not everyone got care packages so when we sent small wrapped candy, it was easy to share. Homemade decorated holiday cookies were a hit. Toll house bars. Chex mix.