In The Fellowship of the Ring, after saving the hobbits from some nasty misadventure in the Barrow-downs (Hobbits never listen), Tom Bombadil lets a big treasure lie outside, to be freely taken by 'finders, birds, beasts. Elves or Men, and all kindly creatures' and hence break the associated curse.
He himself chooses one brooch for his wife and makes some cryptic reference to its previous owner:
He chose for himself from the pile a brooch set with blue stones, many-shaded like flax-flowers or the wings of blue butterflies. He looked long at it, as if stirred by some memory, shaking his head, and saying at last: 'Here is a pretty toy for Tom and for his lady! Fair was she who long ago wore this on her shoulder. Goldberry shall wear it now, and we will not forget her!'
Do we known what lady he was referring to?
Her fairness leads me to believe it could be Lùthien, but I did not find any other elements to support this guess yet, and many other ancient elven ladies such as Idril could match this criteria as well.