Oona is currently my favourite female name. I see the Oo version as ethereal, delicate, fun, and a little defiant (after all, not very many names begin with Oo). I also like
Una, but it gives off a different vibe, and its spelling reminds me of the game Uno and the Spanish article
una.
My top girls' combo is
Oona Christabel Fae.
Here are a few more suggestions:
Oona BeatrixOona CeridwenOona ZephyrineOona SylvaineOona MireilleOona BelphoebeOona Gwenaelle