There's a cartoon stating with "n" called Naruto....
Naruto
Easy, Nelson, the bully
* Naruto * Nana (Peter Pan) * Nutsy (Lady and the Tramp) * Nemo
A beginning and fanmade cartoon that follows after the series "Ed, Edd and Eddy" itself.
Alice in wonderland
Lazy Town
Lazy Town
You could use Ninja Turtles for cartoon characters. They begin with the letter N.
Cartoon Network
Cartoon Network
Jerry the mouse.
Elmer Fudd ,