The Last Letter Game

Gilrean

Nazgûl

Lembas

Silmariën

Nob

Nienor

Lalala. Two answers, silly children 😄
But I'm going with the B because it's a new letter 🙂

Bill the pony! (and you totally have to use the Y because billthepony is one word ✅ )

Yávanna 😛

Aragorn

Nori

Ivonwen

North Ithilien

Nimruzîr

Ringwraith

Hlothram

Minis Morgul

Legolas

Sûza-t

TreeBeard

*Dairondo