I quite like Cassidy, and it used to be among my favorite feminine names (before I discovered Cassia actually wasn't pronounced KASH-uh by most people). It's a little dated (90s), but I don't care; and I consider its sound feminine despite its history as a surname - in fact, the only famous male Cassidys (Cassidies?) I can think of were those with it as their surname, not their first name.
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