Here are a few that I have done for swaps.
"Santa" - the front, all of the pockets are full of embellishments for my swap partner to use, the banner is attached to the outside,
and the back pockets which I have filled with vintage image gifts tags and and attached envelope I made for the "letter".
I like to make a custom box for the folded "Pocket Letter".
"Krafty Christmas" - the front, again filled with an assortment of embellishments, a banner attached across the top (pop dots)
and the back pockets. Here I used a single sheet of paper that I have simply cut and and left in order to recreate the "scene". Again an envelope is attached to hold the "letter".
A custom box to contain the letter. Do a Youtube search to find several variations on creating the box.