The Rugrats Theory
The Rugrats really were a figment of Angelica's Imagination.

Chucky died a long time ago along with this mother, that's why Chaz is a nervous wreck all the time.

Tommy was a stillborn, that's why Stu is constantly in the basement making toys for the son who never had a chance to live.

The DeVilles had an abortion, Angelica couldn't figure whether it would be a boy or a girl thus creating the twins
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As for "All Grown Up" Angelica was a bipolar schizophrenic who, as a teenager became addicted to various Narcotics, bringing her back to her childhood and thus her creations she obsessed over, because of time lapse between the present and the last time she interacted with her creations, she made them older, Angelica was constantally taking hits of acid, so she would never have to live without her creations who were her only company, in a judgemental world

Angelica's mom actually died of a heroine overdose, Angelica was schizophrenic/bipolar because she was a crack baby, additionaly Drew in his depression married a gold digging whore, that Angelica idolized because she fooled herself into thinking it was her real mom, but always had a concept of her mom, Cynthia, and took a barbie doll, and made it after her mom's image, wearing an unwashed oranged dress, and having jacked up hair, which is why she was so attached to it, later in life she followed in her mom footsteps w/ drugs and everything, dieing of overdose at age 13 when All Grown Up! was "canceled"

The only rugrat not to be fictional however, was unborn Tommy's brother Dil, however Angelica didnt know the differace between Dil and her creations, Dil didnt follow her commands, after endless crying and a refusal to disapear like the others did when angelica was angry with them, she hit him. And she hit him, screaming a screaching tune, Stu ran in and pulled his neice off of his only child, but it was too late, he had a brain hemerage, which resulted in a deformation, as he grew up his damage only became more evident, by the time he was 9 in All Grown Up! He lived as an outcast, being ridiculed for his weirdness, and retardation, the immense guilt over this is what led to her drug use and is what led Angelica to un-create the rugrats breifly, until her expericance w/ hallucinogenics.

On a trip to Paris to find love, Chaz married a hooker named Kira (He was actually going to marry a differant hooker, but she just wanted him for his money), who had a daughter named Kimi that was torn from her because she was a cocaine addict (Angelica imagined her from Kira's stories), he lost his mind after the death of his wife and was in denial that she was ever prostitue, upon return to America, Chaz and Kira married and she got her greencard, it was actually a really happy/romantic story, Kira continually stuggled with addiction, but was relatively happy w/ her life, and Chaz

Suzie was actually Angelica's only friend, who entertained the thought of Angelica's creations, for her, She later became a phycologist and teamed up w/ Nickelodeon to make the Rugrats! When Angelica died of drug overdose, she helped arrange her funeral, Angelica's death was sad, because of her addiction, she was expelled from society, which lead to a break with reality, and her eventual death, she spent the last days of her life in the back of the school cafeteria, imagining friends around her, and playing with the lives of her creations.