Earth-Anthropomorphic
Description: Anthropomorphic animals capable of speech exist side beside with humans and have humorous adventures.
Series Examples: Huckleberry Hound, Yogi Bear, Magilla Gorilla, Peter Potamus, Quick Draw McGraw
Earth-Familia (or Flintstone)
Description: A world where humorous family adventures take place. Civilization was very advanced in the Stone Age and dopplegangers of famous people in the 20th Century recur in various eras. By 2062, there is at least one city in orbit.
Series Examples: The Flintstones, The Jetsons, The Roman Holidays
Description: A relatively (in comparison) mundane world of pulpy heroics. There are no costumed heroes and no talking animals, though pets may display near human intelligence.
Series Examples: Jonny Quest, Clue Club, Jana of the Jungle, and Valley of the Dinosaurs and (in the future) Sealab 2020. The unadventurous There Are the Days may also take place in this world, if anyone cares.
Earth-Mystery
Description: A world with a inordinate number of meddling teen mystery solvers and their unusual sidekicks. Some animals here have human-level intelligence and limited speech, but this may not be a universal condition and they are still treated as animals. There is at least one costumed superhero on this world, possibly more. By the 2070s, there is extensive undersea settlement. Astro and the Space Mutts may also take place in this world, meaning the Jetsons's dog has a counterpart in this universe.
Series Examples: Scooby-Doo, Funky Phantom, Captain Caveman, Galloping Ghost and Buford, Speed Buggy, Dynomutt, (in the future) Jabberjaw.
Earth-Superhero
Description: A world of costumed and non-costumed heroes across multiple eras that take on super-villains.
Series Examples: Birdman and The Galaxy Trio, Space Ghost, Mightor, Teen Force, Shazzan, and The Herculoids.
Earth-Impossible
Description: A world of superheroes that are more cartoonish in nature. This may also be the world of the child heroes without adult involvement.
Series Example: Frankenstein Jr. and the Impossibles, The Powerpuff Girls, also possibly the Space Kidettes.