Younger and Junior Versions of Cartoon Characters

Comics

Comic books and strips featuring younger versions of animated characters include:

Captain Marvel Jr., a teenaged apprentice to Fawcett Comics' superhero Captain Marvel, introduced in Whiz Comics in 1941 and later popular in Master Comics and his own self-titled comic book. The character's comic adventures continued until 1953; when DC Comics assumed the rights to the Fawcett characters in 1972, Captain Marvel, Jr. was returned to publication.
Superboy: featured the adventures of Superman as a teenage superhero defending his home town of Smallville from various threats. Other characters seen in this series include the teenage version of Lana Lang, who made some appearances in the adult Superman stories as well. The series ran from 1944 through 1986, when the traditional version of Superboy was retired. A newer version of Superboy exists in the current Superman comics, but this version is a younger clone of Superman.
Little Archie: featured the adventures of the Archie comics gang as elementary school students.
Spy vs. Spy Jr., a running comic strip in the juvenile-themed Mad Kids Magazine (a spin-off of Mad Magazine). Unlike the more familiar version, the junior Spy characters do not attempt to murder one another. Instead, they engage in tit-for-tat pranks and plots (in one episode, a Spy ends up soaked by his own garden hose; in another, a Spy gets splattered by bad-smelling "skunk juice").
Petey: The Adventures of Peter Parker Long Before He Became Spider-Man, a Fred Hembeck backup feature in Marvel Tales featuring humorous stories of Peter Parker, Flash Thompson, and Betty Brant as children, with Aunt May and Uncle Ben. A typical example featured Petey sent by Aunt May to the pharmacy to buy Uncle Ben's medicine and told he can keep the change. not realizing the cost of medicine, he buys sodas for Flash and Betty, only to discover the change from the medicine is a quarter.
Spider-Man and Friends, and its successor, the Marvel Super Hero Squad, feature younger versions of Spider-Man and other superheroes from the Marvel Comics universe.
Little Endless: Child versions of the Endless from Neil Gaiman's Sandman comics, originally appearing in the story "A Parliament of Rooks]", illustrated by Jill Thompson, and subsequently in Thompson's graphic novel The Little Endless Storybook
X-Babies: Several X-Men stories parodied the concept by having younger versions of the cast created by Mojo.
Wonder Woman : Over the years there have been multiple comics involving a younger version of Wonder Woman. Some have been flashbacks comics of her early days, some have been as a result of her becoming younger and some involved 2 younger versions of herself going into the future and teaming up with her. The two younger versions of her are Wonder Tot and Wonder Girl. When writer Bob Haney, erroneously believing that Wonder Girl was a junior protégé of Wonder Woman, used Wonder Girl as a member of the all-protégé Teen Titans, the character was re-established as a genuine junior version to explain her presence as a Titan.