I haven't run across any yet in Fallout 4, although granted I still have a lot to explore, so I want to know if there's anything I should be saving.
If there aren't any of these items in Fallout 4, I'd be disappointed - I liked this aspect of Fallout 3 a lot. It added characterization and it made sense that some items would be worth more to different people, either out of need or out of personal desire.