Notes:

Characters from left to right:
Bubbles from "The Powerpuff Girls"
SpongeBob SquarePants from "SpongeBob SquarePants"
Nigel Thornberry from "The Wild Thornberrys"
Danny Phantom from "Danny Phantom"
Wanda from "The Fairly OddParents"
Aku from "Samurai Jack"
Ron Stoppable from "Kim Possible"
GIR from "Invader Zim"
Sheen Estevez from "The Adventures of Jimmy Neutron: Boy Genius"
Jenny Wakeman (XJ-9) from "My Life as a Teenage Robot"
Billy from "The Grim Adventures of Billy and Mandy"
Bloo from "Foster's Home for Imaginary Friends"
George W. Bush from "New Haven, Connecticut"
Helga Pataki from "Hey Arnold!"
Chuckie Finster from "Rugrats"
Wally Beatles (Numbuh 4) from "Codename: Kids Next Door"