Ilverin:

Another name for Littleheart.

Illúvatar (The Music of the Ainur):

The power that created the Ainur and the World. Also, the Elves and Men. His power seems to be expressed through song and music.

Ingil (Cottage of Lost Play):

The son of Inwë, Ingil led many of the Eldar to the location of Kortirion, the tower, and built the city Koromas.

Inwë (Cottage of Lost Play):

Inwe held the title of King of all the Eldar during the time they lived in Kor. It was he who led the Eldar out into the lands of Men. He was the father of Ingil. The Gnomes called him Inwithiel.

Inwithiel (Cottage of Lost Play):

The Gnomish name for Inwë.

The Book of Lost Tales One (HoME.I)
The Book of Lost Tales Two (HoME.II)
The Lays of Beleriand (HoME.III)
The Shaping of Middle-Earth (HoME.IV)
The Lost Road and Other Writings (HoME.V)
The Return of the Shadow (HoME.VI)
The Treason of Isengard (HoME.VII)
The War of the Ring (HoME.VIII)
Sauron Defeated (HoME.IX)
Morgoth's Ring (HoME.X)
The War of the Jewels (HoME.XI)
The Peoples of Middle-Earth (HoME.XII)