On human-elf relationship, beside Beren-Luthien and Aragorn-Arwen, the most notable that is often forgotten is the other half of their common lineage, that of Tuor-Idril, the latter being a Noldor princess born in Valinor during the Years of the Trees, resulting in the often referenced Earendil, which was the father of both Elrond and Elros, the latter being the first king of Numenor.
Another that is much lower profile but also has direct lore links with LotR is that of Imrahil of Dol Amroth's ancestor with a silvan elf which was a follower of the lost Nimrodel.