Legolas Greenleaf:

The son of the King of the Wood-elves, Legolas Greenleaf was one of the Company of the Ring, and became close friends with Gimli. He was one of the Grey Company on the Paths of the Dead, and was present at the final battle of the War of the Ring in front of the Black Gate. After the War of the Ring, Legolas brought many elves to live in Ithilien. In the year 120 of the Fourth Age, after the death of Aragorn, Legolas sailed from Dol Amroth into the West. Some say that Gimli went with him.

Lalaith:

The daughter of Hurín and Morwen. She died of a plague when she was only three years old. Her name meant "laughter".

Lúthien Tinúviel:

She was the daughter of King Thingol in the First Age of the Sun, and met Beren within Doriath. She fell in love with him, and when her father sent Beren on an impossible quest, to recover a Silmaril, she escaped the imprisonment he had set her in and followed him. Beren succeeded in the quest though he lost a hand, and the Silmaril it contained to the greatest of the Werewolves. When the werewolf was later killed, Beren was mortally wounded, though he lived long enough to place the Silmaril in Thingol's hand, he died. Lúthien chose to follow Beren from Middle-Earth, and her song to Mandos had enough power to move him to pity, something that had never happened before or since. Lúthien and Beren were granted a second mortal life, and eventually died and passed from the circles of the World. She was often called Lúthien Tinúviel.

The Lord of the Rings
The Silmarillion
The Hobbit
The Complete Guide to Middle Earth by Robert Foster