Judge Dredd , Jimmy Neutron , Jonny Quest , Jiminy Cricket , Jabberjaw , The Jetsons , Jem and the Holograms , Josie and the Pussycats , Johnny Bravo , et.al.
Jerry as in Tom and Jerry.
Jerry, from Tom and Jerry
johnny bravo.
Jonny test
jimmy neutron
The Joker?Juggernaut (X-men)
Judy Jetson the jetsons the jetsons
Jade or Jackie Chan from Jackie Chan Adventures.
No there is no Mario character that starts with a J
Jeckle (Heckle & Jeckle), Jerry ( Tom & Jerry)
Johnny Test, Johny Bravo, Johnny Test, etc.
Jerry, from tom and jerry