I can help with Irish names, which are also Gaelic. Fiadh (or Fia) which means deer or wild thing. Orla, meaning fair princess. Saoirse meaning freedom. GrĂ¡inne, meaning grace. You may have to look up pronunciations because I don't know how to go about spelling them phonetically! There are plenty of beautiful Celtic/Gaelic names :)
Gillian, Celia (maybe not unique enough?)
There are also websites that specialize in various national names, you could look up Scottish, Celtic, Gaelic