Elladan, Elrohir: "It is unclear whether they eventually joined their parents and grandparents in Valinor, or chose to remain in Middle Earth."

Thranduil: "After the fall of Sauron, Thranduil fixed the southern boundary of his realm as the Mountains of Mirkwood, and his realm flourished well into the Fourth Age. He may have stayed on as the king of the Great Forest or left Middle-earth and departed to the Undying Lands."