The classic Hanna Barbera shorts and the Cartoon Cartoons of the 90s/early 00s take place in the same universe during various points in time.
Here's a rough time line:
- Distant Past:
- Near Past:
- Near Past/Present/Near future:
- Near future:
- 25-30 years in the future:
- Mandark's reign "Ego Trip"
- 40-50 years in the future:
- 100 years in the future:
- 150 years later
- Aku successfully takes over the world
- 500 years later
- Jack arrives from the past
- 540 years later
- 580 years later
- The result of an environmentally minded rebuilding of society. (Alternatively, an After the End Scavenger World scenario).
- The Flintstones (retain much of the scientific knowledge of the past generation, Fred isn't that smart but developed a shrinking formula during one of his "inventing kicks").
- 800 years later
Human-kind develops Franklin Richards
or Haruhi Suzumiya
level reality warping through a result of genetic engineering and Hollywood Genetics. As a result, humans gain the ability to create living constructs with there minds (ie: imaginary friends). While people are capable of creating these entities throughout their lives, creating something like that is considered childish. As such creating these contructs end during early late childhood (with a brief reawakening during the teen years *the extremeasaurs*).
Hanna Barbera/Cartoon networks talking animals are imaginary friends. Friends who do not get adopted eventually establish their own community. They eventually rediscover time travel and arrive in various places in the past.