Not that anyone cares, but since others have posted their opinions, I'll add mine. As for the item of "significance" - if it made the parents happy, as has been indicated numerous times, I would think it would be some method of communication which indicates Holly is still alive or was alive later than the initial date of the kidnapping. Such items include - a cell phone with usage records, photos, or memos dated after that date OR handwritten or other communication from Holly indicating she is still alive or her whereabouts. The only other thing I can think of that would make me happy as a parent would be an item that helped point to her location or helped ID the perp. In other words, something that confirmed LE or family suspicions of her whereabouts or her abductor. Not sure what that would include.
As a parent, another random item of personal property wouldn't mean much. The key is knowing she would still be alive, who took her, and where she was.