I said other, because this list did not include the following:
Bullwinkle J. Moose(Rocky and Bullwinkle)
Dudley Do-Right
Tom Slick
George of the Jungle
Leopold "Butters" Stotch and Randy Marsh(South Park, they're both stupid and gullible)
Bebop and Rocksteady(Teenage mutant Ninja Turtles OS)
Stan Smith(American Dad)
Mr. and Waldo Magoo
Chris Griffin(He's genuinely dumb without help, so he's dumber than Peter, who is a fat, stinking drunk)
Brian Griffin(You should hear what Quagmire has to say about him, it'll disprove any chance of intelligence he might have)
Steve Smith(American Dad, He's Dumber that his father)
Bloo(Foster's Home for Imaginary Friends(Face it, he's dumb))
Roger(American Dad, He's dumber than the human race)
Hoggish Greedily and Sly Sludge(Captain Planet, the least intelligent Eco-Villains)
Hank Venture and Rusty Venture(The Venture Bros, the stupid Twins of their sets)

There are others, but I could go on forever...