Skill-Out refers to the largest armed Level 0's group in Academy City, which have numbers up to thousands. Their goal is to fight for rights in a city where those without abilities are picked on by those who flaunt their higher esper abilities, while the authority sometimes turn a blind eye to the injustice or just can't help.
Members' fighting ability are generally weak, with the average fighter having brawling skills below that of an individual with martial arts experience or lots of street-fighting experience. Some members carry weapons such as collapsible large blades and guns that are as lethal as Level 3 esper abilities. The favored tactic is to swamp the esper with numbers when fighting since one on one they cannot win normally.
Recently there has been an increase in the number of Skill-Out gangs within the 10th district, where they've taken to destroying the cameras and security bots that would otherwise alert Judgment to their activities. This has made the 10th district a bit inhospitable to those who possess ESPer abilities since their large numbers have made the Skill-Out gangs in that district more confident and aggressive against those they see as their oppressors in Academy City.
Despite the thought of most civilians that Skill Out is one big group working together, the reality is that Skill Out is the name given to each gang of delinquents and criminals, with each group adopting their own gang name to differentiate themselves from the other Skill Outs. How a leader is chosen may vary from gang to gang, as can a gang's philosophy towards people more gifted with psychic powers though it's always at least somewhat hostile.
Jaguar: The Jaguars are notorious for being a group of savage anarchists. Because of their chaotic and violent history, it is unknown when they became a proper Skill Out or what they were like before they became a pack of thieves, raiders, and vandals. They are usually at an uneasy truce with other Skill Out gangs, though some of the less unscrupulous gangs may try to manipulate and use them for their own purposes. Even though the Jaguars are not numerous, they're unpredictable and utterly bestial. Other Skill Out gangs and even Academy City forces have exterminated this gang several times in history, only for them to appear again some months later, under a new leader. It is possible, then, that the Jaguars are not so much a proper gang as they are the haven for the worst malcontents among the inhabitants of The Strange. Jaguars are ultimately only nominally a Skill Out gang; they typically care little for fighting for the rights of Level 0s. If they attack an ESPer, it's because they're bored, not because they have any noble intentions. Because they're such a chaotic group caring only for their own perverse pleasures, they are more likely than other Skill Out gangs to recruit disenfranchised or fugitive ESPers into their group.
Psyche Hunters: The Psyche Hunters are a Skill Out gang known in other districts for their vigilante attitude towards the bullying of non Power users. Using a rudimentary intelligence network established through non District 10 informants providing information via phone, chat sites, and word of mouth, the Psyche Hunters target Power Users known for bullying those less psychically gifted. Through a combination of anti psychic tactics, information about the target's powers, and numbers, the Psyche Hunters do their best to protect the "little guys" from the bullying clutches of ESPers who let their power get to their heads. All is not well, however; recent upheavals in the Psyche Hunters' hierarchy has all but split the gang in two, one group favoring vigilantism only against bully ESPers and the other preferring to target ESPers indiscriminately. The less scrupulous group is beginning to call itself the Psyche Raiders.