As far as I'm aware, it's not a recently created name but anyway...I love this name! It doesn't feel too girly, but still very much proudly feminine, like the sort of name you'd give a heroine of a fantasy novel.
I really love the name Delyth. It sounds like delight or delicate and is indeed delightful and delicate. It also makes me think of flowers and a lapping, splashing stream and nature in general. This is one of my most favourite Welsh names, though I like a whole lot of them. I agree with the previous commenter that it indeed sounds kind of elfin and fairy-like. It also makes me think of harp because of Delyth Jenkins. I think for people who aren't Welsh but live in the Anglophone world, it could make an interesting alternative to Delilah if you like Delilah but for some reason don't like it enough to use it, Delyth's crispier and definitely much more uncommon, at least outside of Wales, I've no idea how popular it is in its home country, but if you like Delilah, want something uncommon for your baby and perhaps have some Welsh heritage I think Delyth would be a cool option, especially that its pronunciation is very straightforward.