I prefer Fenna to Fenella too! But I don’t think the similar Calla is as cute as Amelie. I also don’t like Cal/Callie. I prefer Hallie/Halle or Holly. Ingrid to me is as chic as Amelie and Indie gives you a casual nickname.
Here are a few others, based on Louisa, Fenna, Calla & Ingrid (though not confident in any landing based on our low strike rates on this thread ;)!):
Gwen / Gwyneth / Gwenith / Guinevere / Gwenevere / Gwenna / Gwyneira
Merryn
Wenna
Keira
Bronwyn
Sunniva
Lowenna
Faye
Farrah
Georgia
Petra
Livia
Harriet
Jane
Dorothy
Josephine (Josie, Joey, Posy, Phina)
Neve / Niamh
Elsbeth (though for Elsie or Beth not the overused Ellie/Elle)
Imogen (Immy/ Ginnie)
Noemie / Noémie (too close to Amelie?)
Tove
Suvi