My best friend is getting married in a little over a week. I plan on giving them a cash gift but want to accompany it with something else that will be memorable- some sort of keepsake. So I'm wondering, what keepsake-like, non traditional, non-registry wedding gift did you receive and appreciate most? Or what gift of the sort have you given in the past that you know the couple really enjoyed?
They do not have a registry. I know, please don't get into the etiquette of it here. That's not the topic. If you must know they live overseas (apartment is rented fully furnished) and won't be returning to the states until almost two years from now so they would have no where to keep household items for the future. Their wedding guest list is really small and intimate so everyone who is attending knows the situation and knows that giving them any household items would be pointless. This is why I'm looking for something small and along the lines of a keepsake.
ETA: Check the comments