[Lothiriel Silmarien]

This is very hard to pick, but I have read several times that Feanor was the greatest of the Eldar. So in my opinion I would think Feanor, Luthien, Finrod Felagund, Fingolfin, and galadriel. By the time of the War of the Ring, who else was there that old of the elves? Not a lot. Most of them were from Beleriand, and Galadriel did see the light of the two trees, so she was very old. And she grew wise every year.