Jaeger
Jaffa
Jag
Jagger
Jago (A character in a Victorian book who battled against the odds)
Jaguar
Jai
Jai Alai
Jailbait
Jailbird
Jaina
Jaka
Jake
Jakey
Jakob
Jakoby
Jakov
Jala
Jalapeno (after a chile pepper)
Jalina
Jama
Jamaica
Jamal
Jambo (Swahili for "hello")
Jamee
James
James Belushi
James Brown
James Dean
James T. Kirk