List of fan-created Factions/Sects and their philosophies?

Here are a number of factions I use that I created or lifted (and I'm trying to give credit as best as my memory can serve me)

-ABOLITIONISTS
(The Liberators, the Emancipators)
This group believes that freedom is the greatest gift in the multiverse. For this reason, they seek to stop all slavery. Unfortunately the group has different views of what constitutes slavery. Most also seek to lift all forms of mental control or coercion (e.g. subjects of Charm or Geas spells). Some members even seek to free all captives, even evil gods in Carceri and agents of destruction like the Fernis Wolf. One small subgroup even believes that the Lady of Pain is a prisoner and they secretly (very secretly) work to set her free (“Unlock the Cage!”).

-The BROTHERHOOD of BELIEF
[Largely taken from another contributer]
(Eaters, the Hollow)
The Incantifers eat magic. The Prolongers eat life. Well, the Faithless eat belief. Originally they were a sub-sect of the Athar. According to the chant, an Eater could just talk to someone and drain them of their beliefs, stealing the faith right out of their minds. In the beginning the Eaters were just the elite of the Athar, nothing more; but eventually they started feeding off of the faith from every faction or sect they could find. They were banished from Sigil for the danger they posed

-The BROTHERHOOD of the SPHERES
(The Leeches)
This group is greedily seeking to siphon power off of the trapped gods/primordials of Carceri. Most scholars dispute if this can actually be done and what the consequences would be if possible. The faction tries to keep their activities secret. Some members want to become gods, others rationalize their acts as a means of keeping the imprisoned beings weak.

-CABAL of PERFECTED MOMENT
[Largely taken from another contributer]
(The Rapiers, the Deaf)
With the right action, done in the right place, with the right clarity of thought and purpose; one can change the course of a life, of a destiny, a world and possibly the multiverse itself. (“For the want of a nail…) This cabal seeks to change the fates of themselves and others, mostly with their weapons. These persons do look for conflict, but only use their weapons with purpose to strike at select individuals in the field of battle, for to shape possibility with just a single action. For each Rapier it's all part of a quest for clarity, when to act and what to do for the one perfect moment in destiny.

-The CAMPAIGNERS
(Recruiters, Warmongers)
Based in Acheron
Some say that war is Hell; but this faction secretly believes that insight comes from the conflict. For this reason, they are always seeking to challenge any group that grows in power while appearing to serve (and recruit) neutrally. They are like the yugoloths in this way. They feel that only by joining a cause (as opposed to just visiting a plane) does one really experience and understand the philosophy being argued.
Those who know the deeper intentions of the faction say that they seek to bring about Ragnarok.
To the uninitiated, they seem like amoral recruiters trying to meet quotas to fill whatever mercenary force has hired them. “Join the ; see the Planes”. They also set up combat in the Great Arena in Sigil

-CARETAKERS of the MIND
(Inmates, Madmen)
Based in Pandemonium
This faction believes that the deepest insights into the secrets of the multiverse can only be found in the flashes of brilliance of the insane whom they feel to be the only who are actually been enlightened. Some seek to cure the insane so that they can relate their discovered wisdom. Others within the faction actually seek to induce madness in others.
I changed cannon so that this faction runs the Gatehouse Asylum and the Harbinger House and provide a service by providing for the harmlessly insane and by detaining the dangerously insane. The Caretakers are especially interested in madmen who have extra powers based on their illnesses

-The ESCHATON
[Largely taken from another contributer]
This faction is actually more of a cult that at first glance seem to share a lot in common with the Doomguard. They worship mysterious chthonic powers and believe that all creation will be swallowed back. They attempt to arrange things prophesized to bring this about (actually visions sent by some dark god(s) from the Far Realms to arrange things as it wishes them to be?) They feel that all the multivese is a bubble of thought needing to be burst; and they believe they will gain power in the new primordial order.

-EVOLUTIONISTS
[Largely taken from another contributer]
(Darwinists, the Sadists)
This sub-sect of the Godsmen seeks to harden themselves by enduring the elements of the Inner Planes. Surviving in the elemental planes force one to think about survival rather than petty matters such as belief. They force him to strengthen and protect himself with powerful magics in order to stay alive. A person coming to the Great Ring from the Inner Planes sees the dwellers of Sigil as pampered weaklings, and there's a reason for that, too. The Inner Planes are proof positive that life in the face of death improves oneself.

-FORGESMITHS
(Inventors, Gearheads, Prometheans)
Based in Bytopia
While most well-known for their various inventions, this faction is actually seeking to increase the inventiveness of all beings throughout the planes. They feel that the multiverse is a sleeping being that is just now rousing from its slumber. They feel that raising the collective creativity through the multiverse will lead to further awakening and to new levels of consciousness. They see the creation of the Endless Staircase linking points of creativity as vindication of their beliefs. They always seek to find a new way to accomplish things; and try to never repeat a way that’s been tried before. Some members expose people to “tests” and then reward those who succeed (e.g. a destitute woman might be challenged by a test and then rewarded with cash if successful)

-The GUILD of SHADOWS
[Largely taken from another contributer]
(Shadows)
Rulers are always vulnerable to the worst of their flock, exposing themselves to assassins, poison, and accidents. It is much better to rule from the shadow behind the throne. When figurehead after figurehead dies at the hands of irritated citizens, the true ruler lives securely in the lap of luxury and the seat of power. Power isn't to be challenged, but to be controlled. From the shadows.

-ILLUMINATED
(Sore-sports)
A Merkants subsect that believes that anything that they cannot control must be destroyed

-INCANTIFIERS
[Largely taken from another contributer]
(Touched)
A sect composed of wizards who find meaning in accumulating magic. They have found a way to escape old age and death by consuming it. More advanced members are reported to no longer need to eat, drink or perhaps even breathe provided that they have magic to sustain them. Most of the advanced members need to consume at least one magic item per month to survive.

-The IRON RING
Based in Gehenna
The Iron Ring is a mafia organization trying to quietly exert influence on all criminal activities in Sigil and the gatetowns. They believe that life is ugly, brutish and short and that the best one can do is to accept this “truth” and make the most of what one has. To do otherwise is to be a chump.
The Iron Ring is composed of five families; but in Sigil, only two of these families are active.

-JESTERS
(Imps, Pranksters)
This faction seeks to up-end the existing order to change people’s perspective. Unlike the Revolutionary League, many of their efforts are non-political; but unlike the Xaocists, their causes tend to have a point of making people think (e.g. pulling some stunt that causes one to question the moral implications of eating meat or using a warforged as a servant).
They feel that life is a joke that we don’t get. Since jokes hide a deeper truth, this faction feels that the only means to get closer to the Truth by increasing humor and expanding perspectives. In this last vein, they also are very active in finding and opening new portals as it is only through cross-pollination that new ideas come into being.
For example, they once pumped hallucinatory gas in the Sigil Gymnasium which caused hundreds to be late for work, but they'd say they're just teaching people to loosen up. It wasn't an attack, it was an education. Once people see how little it mattered if they’re late for work or not, people would learn to take life a little less seriously. Nothing is worse than taking yourself or your philosophy too seriously.
-GREMLINS
(Monkey-Wrenches)
A Jester subsect centered in the Lower Ward that covertly sabotage things in order to create absurd situations that will hopefully, in turn, get people to question the existing status quo.

-LEGISLATORS
(The Ruled)
The Guvners have got it backwards! They say we're all governed by laws. In fact, laws are things created by people, not things that create people. But since belief is power, if one believes in a law; it becomes true. It is the purpose of the Legislators to be the driving force in the establishment of laws that will allow them to control the multiverse.

-RESIGNERS
[Largely taken from another contributer]
A sub-sect of the Fraternity of Order. They believes that Murphy Law’s trumps all others. The Bleakers like them

-The REVEALING LIGHT
(Shiners, Illuminators, Nosy Berks)
“A little knowledge can be a dangerous thing.” “There are some things mortals were not meant to know.” “It’s none of your business.” Such words are blasphemous to a Shiner. Knowledge is meant to be learned, understood and shared. By keeping secrets to yourself, you are benefiting no one and holding back the progress of society.
The Shiners have compiled a massive database that is growing larger everyday. To add insult to injury, it’s entirely open to the public. The Shiners are very proud of the fact that anyone can just walk in to their libraries to learn about a multitude of subjects.
Of course, there are many people in the multiverse that loathe giving up their secrets. The Revealing Light wishes that it didn’t need to come to this, but the faction remedies this by sending out people known as “agents” across the face of the multiverse. Their purpose is to collect data and uncover secrets that many forces wish to remain hidden. At first, many of the movers and shakers of the planes found the attempt laughable. That is until a Shiner agent managed to infiltrate the Arcane Tower and made off with a number of manuscripts detailing some of the yugoloth’s plans regarding the recent turns in the Blood War. Now, most people are wondering just how far the faction will go before things turn ugly.
On a more mundane level, they are also knowledgeable about all the gossip in the city
This faction runs several public libraries in Sigil

-SANCTIFIERS
(Dunkers, Baptists)
A Cipher subsect that believes that the mental and emotional baggage of one's life is what holds one back; and that it can be wiped clean by a dip in the Styx.

-SEEKERS of the UNKNOWN
A Signer subsect that seek to find the Higher Power in the multiverse that they believe is the true imaginer of the multiverse

-SLAKERS
Whatever

-SPIRE-BREAKERS
[Largely taken from another contributer]
(The Breakers, the Low Men)
An Anarchist subsect that feels that the Great Wheel is an abomination. It holds the planes captive in a neatly balanced ring. It hides the true infinity, offering us a false one. Free yourself! Shatter the Cage! Anything you can imagine can be possible if you are set free! They have become too cosmologically-bent to focus on a mere political agenda of the Anarchists.

-The STAR CHAMBER
A Mercykiller sub-sect that seeks to punish those that they feel eluded traditional justice (e.g. free due to lack of evidence)

-The UNBENDING PATH
(Roters, Muls)
This faction believes that the status quo must be preserved or the universe will be destroyed. They believe that their devotion to tradition and efforts to maintain the multiverse will elevate them in mystic and psionic power. Ultimately, they seek to find the binding ritual that will uphold order and banish decay and chaos forever.

-UPSPIRES
Signer subsect believe the ring of Sigil is a portal that a god could use to ascend to a higher state (provided the Lady wasn’t blocking it)