Here is a list of the different factions that can be found in this setting. This is not an exhaustive list and this list is intended to cover a faction type. Hopefully this will allow me massive scope to get creative with tabletop forces and terrain.
Factions.
Enforcers
The Enforcers are the police of the city. Well armed and trained they try to keep order. When arrests are made they are shipped to the halls of justice and sentence is passed by a Judge. Often the Enforcers deal with the mundane policing duties such as traffic, routine patrols, clean ups or security. Enforcers will often support any Mags in the area.
Magistrates
The Magistrates or Mags as they are known are the feared elite of the cities Law enforcement. They wear improved body armour and carry better weapons to the Enforcers. With 15 years of training the Mags are authorised to carry out on the spot justice . They are judge, jury and executioner. They will often arrive at riots and block wars and wade in.
The Mags act as the cities defence force and provide defence from Wasteland gangs and some upitty newly formed wasteland states. Occasionally the Mags will go out into the Wastelands to deal with raiders or criminals. Becoming a Mag is a massive responsibility. Once a Mag always a Mag. If they survive they can rise up the ranks and end up a judge or counsellor. However all Mags face retirement one day – those that do have to wander into the wastelands or undercity to bring the law to the lawless. They never return.
Brat Gangs
Brat gangs come from the Lux Blocks where the rich dwell. They have the best stuff and are often targets of poorer gangs.
Bounty Hunters
Bounty hunters are employed by the Mags. The go out into the wastes looking for those fleeing justice and bring them back dead or alive.
Cit-Def
The Citzens Defence force is a volunteer militia. Citizens gather and train in case the city is invaded. The Mags think its a bad idea to train and arm citizens. 60% of blocks having a Cit-Def unit and they sometimes get involved in block wars. Each Cit Def unit has its own uniforms and equipment which varies greatly in style and quality. Often the block Name influence uniform and equipment. It is rare if two Cit Def units look alike.
Cit Def units spend a week at a time at the Outposts. Training missions into the Wastelands, Nuclear Alley or the undercity are also taken. Sometimes they don't come back.
Corporations
There are many corporations in the city having a block or two which the use to produce goods to sell to Utopia City’s residents. Kraptoidiots Corporation is the largest corp in the city. Corporations often try to out do each other and steal each others designs. This can lead to out right warfare between them.
Cults
Many turn to cults as a way to cope with day to day life in the City. Many cults are shams to pick the pockets of the gullible, some genuinely want to help, others seek enlightenment but there are darker cults with death cults killing as many as they can or suicide cults wiping themselves and huge portions of the population out. Then there is the problem of My God is Better than Yours syndrome where cults set out to destroy each other in some imaginary holy war.
The Cult of the Mattblackgod is the most popular cult in the city.
Gangs
Every block has a gang. Some blocks have up to three. Each gang has a unique look or set of colours that distinguish it. Gangs are made up from youths with only a hand full of adults remaining with the gang. Many don't make it to adulthood. Those that do may find jobs in the Orgs or (very rarely) become model citizens.
Mercenaries
Mercenaries are often employed to deal with a problem outside the city, often with a Mag in support.
Out in the Wastes there is many who employ Mercenaries to keep bandits and raiders at bay. Mercenaries can be anything from a few hired guns through to full squads of highly trained well equipped warriors.
Orgs
The Orgs are the Organised crime syndicates of Utopia. The are involved in all manner of illegal activities. Org gangs have a distinct look. Often suits are the uniform they wear.
Under the streets:
The Ratmen/Vermen
No one knows for sure where the Ratmen came from. Some claim they evolved from rats after the nukecast and others claim they where made in a lab. What ever their source these strange Rat Men exist under the city and intelligence gathered from other cities show that Utopia is not alone in this invasion. They live in the depths and come to the surface to raid. Ratmen are often seen with giant rats who act as lookouts and additional muscle.
The Grotz
These strange little men are also called goblins or Mutiemen. They are often green but also come in a range of browns with human skin tones also being common. It is thought that these creatures are mutants. They live deep in the tunnels and love old shot gun style technology. Anything with a loud bang and a flash is loved by the grots. They rarely come to the surface but will often attack Scavs and Ratmen.
Trogz:
The Trogz like the grots are mainly green but can come in a range of browns and human skintones. They where developed for a war but never saw action. They where thought to have been destroyed when the Nuke Cast happened. The Trogz where tougher than Humans and survived. They escaped and have been living and raiding ever since. They have found a way into the tunnels from the wastelands and enter to raid the grots, Ratmen and scavs. They are seeking a way to the surface to slaughter the humans.
Some Trogs are employed as Mercenaries by the Mags and see action keeping the city safe. Other Trogs gain employment by those with darker agendas.
Scavs
Scavengers live in the Undercity having slipped through the cracks of the system. The raid into the city at night to grab the unwary who get dragged down into the darkness to become dinner.
Mutants
Various types of mutant exists under the cities streets. Many have fled from the city above their mutations to severe. They form bands under the city. Wild mutant beasts are also found in the dark.
Rats & Bug
Mutant Rats and bugs are commonplace under the city and are a danger to those who dare wander under the city.
Rogue Robots
With so many working Robots in Utopia some break their programming protocols and head off on their own (telling them there is no Silicon Heaven usually does the trick). They often head into the undercity where they form gangs.
Smoggers:
Smoggers are a strange mutation of mole that live in the udner city. They form bands and compete for resources. These mole men are ideal for living in these conditions. Smoggers can also be found out in the wastelands. Smoggers sometimes make pacts with the Vermen/Rat men.
Out in the Wastes:
SettlementsThere are many settlements out in the wastes. There are many with up to 20 people living in them. They scale up in size to full blown cities (Liberty City is the largest with 15 thousand people living there). It is often ill advised to pick a fight in these places. Everyone is armed and usually have some experience. They fight every day to survive.
Bandits
Bandits live in the Wastelands. Some are criminals from Utopia fleeing the Mags others are Wastelanders born and bred. Bandits raid Utopia traders, prey on Stalkers and keep wasteland settlements in fear. Mags will often act when warbands get too large.
There are also bandits that operate as Pirates on the Dread Seas and there are some bandit clans that specialise in raiding airborne transports. It seems beyond the walls no where is safe.
Warbands
Warbands are raised from settlements and go to war or raid others. They often compete with Bandits for spoils. Some times a Warband is raised to rid a place of bandits.
Warbots
Out in the Wastes many old warbots sit inactive waiting for something to reactivate them. Stalker and Scrap Wranglers love to find such bots. However they must take care for many of them are just waiting for the next thing to kill. Old Warbots are banned in the City.
Scrap Wranglers
The Scrapwranglers head out into the wastelands in huge vehicles looking for salvage. They haul this back and sell it to the Corps for recycling. The often fall into trouble with the Stalkers.
Stalkers
With unemployment so high in Utopia some consider the dangerous job of routing around the wastelands and ruins looking for items of value some of which can fetch high prices from collectors. It is a dangerous job and many stalkers are viewed with both awe and suspicion. Stalkers often camp close to the Outposts as many find they cannot adjust back to life in Utopia. Stalkers are at times hired by the Mags to act as guides.
There are a few different gangs of Stalkers (or Clans as they call them) and they sometimes get into conflict over claims.
Tribals
Tribals exist in the wastes. They have lipped to a more primitive state and live off the land. Some regard the local ruins and tech as evil. Others worship it. Generally the old places near their homes are regarded as sacred.
Rogue Mags:
From time to time Mags go bad. They are corrupt and flee the city when they have been discovered. Rogue Mags form bands or lead packs of bandits that raid Utopia merchants and traders.