I personally think it’s a bit overdone being #15[name_f][/name_f] (in the USA, at least and will likely only climb higher since [name_m]Justin[/name_m] and [name_f]Hailey[/name_f] Bieber picked it…)
[name_f][/name_f]Other names that are a bit less common but still bring an edge and have the same initial sound:
[name_f][/name_f][name_m]Jett[/name_m] (this one is trending upward, though)
[name_f][/name_f][name_m]Jacques[/name_m] ( a little cheeky lol)
[name_f][/name_f][name_m]Jameson[/name_m]
[name_f][/name_f][name_m]Joel[/name_m]
[name_f][/name_f][name_m]Jensen[/name_m]
[name_f][/name_f][name_m]Jorah[/name_m]
[name_f][/name_f][name_m]Julian[/name_m]
[name_f][/name_f][name_m]Julius[/name_m]
[name_f][/name_f][name_m]Gentry[/name_m]
Cool middles for [name_m]Jack[/name_m] if that’s what you land on:
[name_f][/name_f][name_m]Jack[/name_m] [name_m]Xavien[/name_m]
[name_f][/name_f][name_m]Jack[/name_m] [name_m]Maximus[/name_m]
[name_f][/name_f][name_m]Jack[/name_m] [name_m]Orion[/name_m]
[name_f][/name_f][name_m]Jack[/name_m] [name_m]Atlas[/name_m]
[name_f][/name_f][name_m]Jack[/name_m] [name_m]Gray[/name_m]
[name_f][/name_f][name_m]Jack[/name_m] [name_m]Whittaker[/name_m]
[name_f][/name_f][name_m]Jack[/name_m] [name_m]Thane[/name_m]
[name_f][/name_f][name_m]Jack[/name_m] [name_m]Thatcher[/name_m]
Hopefully these help!