I always loved the posergangs. I felt that they added a dash of total craziness to the whole thing.
Seen through the lens of maturity I think that they could be a great critique of the modern cult of celebrity.
Since we are talking about what could be I thought I'd list the posers that were in the old CP. Note that all the write ups are R. Talsorian's not mine.
Bradi Bunch: A small time family posergang, based on an old vidshow. The older members protect the "children" of the gang. Membership consists of runaway or orphaned children.
The Gilligans: A militant gay posergang, also based on an old vidshow. Members include Skippers(leaders), Professors(techs), Maryanns & Gingers(transsexuals) , and Gilligans(initiates). The Gilligans have recently moved from the Marina District (forced out by the Wild Things.) and have settled in the park.
The Kennedys: A posergang centered around the famous Kennedy family of the late 20th century. The Kennedys have no turf and can be found in any area of the city, from JFK in the Corprate zone to Bobby in the Combat Zone. Many suspect the leader of the gang is going to run for mayor next term.
Edison's: This posergang patterns itself on famous inventors. They relish the ingenious and sadistic. Second only to the Brainiac's for ingenuity, they excel in the construction of deathtraps and the like. Their turf is located in the eastern residential district.
The Fangs of Justice: This group of psychotics patterns itself after famous crimefighters of fiction. They like to think of themselves as a guardian gang, but in truth, will terrorize anyone they can get their hands on.
Western Stars: A combat posergang that idolizes western gunfighter philosophy, and mimics great gunslingers from film and video. The Stars use revolvers and are big an "fair" one-on-one gunfights. They keep their turf in the upper westside of South Night City.
The Valentino's: This posergang dedicated to the pursuit and seduction of the most attractive women in Night City. Experts in seduction, the more unattainable a woman is the more they try to bed her.The Valentino's only meet once every three months, to compare scorecards. The only danger the Valentinos pose is to men whose wives or girlfriends have an ATT of 9 or more. They will pursue these women until the bed them, or are scared off.
Personalities: One of the strangest posergangs in the City. When someone joins the Personalities, the person he will be Biosculpted into is picked randomly; If you get Lana Turner, you're Lana, if you get Abraham Lincoln, be ready to wear stovepipe hats. Your rank in the gang depends on how well you adjust to your roll. These people are the ultimate posers; once they are dropped into their roles, they live the life. All members can be recognized by the fine steel neck band they wear.
They could be arguments made that the Jack the Rippers, Bozos, and Philharmonic Vampires to be added to the list but, while the Rippers are not classified the others are prankster gangs in the book.
I could've sworn that there was a Trekkies gang in the books somewhere though.