I love the name Heledd so much! It is Welsh (and I love the Welsh language and have been learning it for a few years), is the name of Heledd, princess of Powys who was already mentioned by other commenters, whose character I like a lot, I like that this name has such a long tradition. It sounds so sweet and, moreover, sounds very similar to Helen, which is a long-standing favourite of mine. I love the idea of nicknaming it to Heli like another commenter mentioned.