[name_f]Petra[/name_f] is absolutely beautiful! [name_f][/name_f] She’s one of my favorites. [name_f][/name_f] I love your taste already. [name_f][/name_f] 
Here’s a few ideas:
[name_f][/name_f]Irene/Irena/Irina
[name_f][/name_f][name_f]Katerina[/name_f]
[name_f][/name_f][name_f]Lark[/name_f]
[name_f][/name_f][name_f]Lillevi[/name_f]
[name_f][/name_f][name_f]Esther[/name_f]
[name_f][/name_f][name_f]Tess[/name_f]
[name_f][/name_f][name_f]Romy[/name_f] (although maybe not ideal with your surname, is [name_f]Ramona[/name_f] nn [name_f]Romy[/name_f] any better?)
[name_f][/name_f][name_f]Georgina[/name_f]
[name_f][/name_f][name_f]Zinnia[/name_f]
[name_f][/name_f][name_f]Adela[/name_f]
[name_m]Caspar[/name_m]
[name_f][/name_f][name_m]Soren[/name_m]
[name_f][/name_f][name_m]Jude[/name_m]
[name_f][/name_f][name_m]Julian[/name_m]
[name_f][/name_f][name_m]Finley[/name_m]
[name_f][/name_f]Maxim/Maximilian
[name_f][/name_f][name_m]Isaac[/name_m] (not that unusual, but I like him with Petra!)
[name_f][/name_f][name_m]Irenaeus[/name_m] or [name_m]Ignatius[/name_m]
[name_f][/name_f][name_f]Vale[/name_f]
[name_f][/name_f][name_m]Simeon[/name_m] (probably too similar to [name_f]Petra[/name_f], though, given the whole [name_m]Simon[/name_m] [name_m]Peter[/name_m] thing)
[name_f][/name_f][name_m]Andreas[/name_m]
[name_f][/name_f][name_m]Florian[/name_m]
[name_f][/name_f][name_m]Amory[/name_m]
[name_f][/name_f][name_m]Otto[/name_m]
Good luck!