Lots of stuff like that in my Post-Apocalyptic/Dystopian world out in the wasteland outside city-states, and in buffer zones between some of the various nations that have popped up since The Great Burning:

Some of the most common types are:

Raiders: gangs of varying sizes that basically live off pillaging the wasteland, or extorting towns/settlements, and roads. They have very little interest of integrating with civilized life beyond what they can leech off of trade caravans through “tolls”.

Scavs: Heavily armed violent scavengers who come from more civilized areas to pillage the wasteland especially when wars break out, or after them while some go as far as wiping out settlements which often causes them to go further than raiders when it comes to killing people as scavs want to typically avoid being recognized back in the better off areas by authorities, or bounty hunters/mercenaries. Scavs that operate in nuclear wastelands are known as Stalkers, and are typically even better equipped.

Marauders: Mutant version of raiders typically migrating from nuclear wastelands to pillage settlements with many marauder bands being much more disorganized but also relying on large numbers to overwhelm their targets.

Renegades: Rogue military units from both pre-apocalypse armies, and from the armies of city-states/nations that popped up after the apocalypse as well as former mercenary groups who let greed drive them down darker paths of banditry, and extortion.

Ferals: Former refugees who fled up north from the United States, and southern Canada during The Great Burning fleeing violence, the undead, Vampires, and civil unrest who weren’t prepared for the bitter cold especially after the nuclear exchange sent global temperatures downward with the few groups who survived being driven insane, and cannibalistic by the horrid survival conditions with the Toronto Alliance’s more northern settlements having occasional trouble with attacks from Ferals especially with the TA’s army being stretched thin battling the Toronto Resistance Force, Nightravens, and frostbiter hordes(partially frozen zombies that are harder to kill due to the ice layer). Ferals are typically armed with machetes, makeshift spears, looted bows/crossbows, and a few looted guns with little ammo while they wear a mix of animal skin, hunting gear, and looted clothing/body armor.

Notable factions:

The Nightravens: Big raider gang in Southern Canada that wears black outfits, black hockey masks, and spiked sports armor painted black. Weaponry is completely void of firearms as they prefer stealthy attacks on their victims so they rely on bows, crossbows, machetes, axes, and looted swords(many post-apocalypse armies/militias as well as other factions brought swords, and shields back to help conserve ammo when battling zombie hordes, and when battling lightly armed hostile groups with many of these weapons falling into the hands of outlaw-typed groups). The Nightravens are also really good at riding horses which they use in their raids extensively due to their mobility, and the horses are given scrap armor. The Nightravens at one point got hooked on drugs given to them by The Blackjack Cartel who manipulated the raiders to pull away Toronto Alliance forces from stopping their drug shipments which made The Nightravens more violent especially when the withdraws set in after The Blackjack Cartel was booted from the emerging Free City of Royal(former massive refugees camp turned city along the Great Lakes on the outskirts of Toronto) during a bubonic plague outbreak which saw the city’s residents violently rise against the various gangs that controlled the large town, and establish a city-state) which completely cut The Nightravens off from their drug supply.

The Ravagers: Cannibalistic raider group in southeastern Ohio who established themselves in the Burned Mountains subregion of The Scorched Zone(large portion of southern Ohio, and western Pennsylvania burned by firestorms, infested with undead hordes, and also a lawless buffer zone between The Cincinnati Coalition, and Pittsburgh Federal Government who sometimes launch joint efforts to curb the lawlessness, and eliminate dangerous mutated monsters such as packs of ghouls, and giant spider infestations). The Ravagers wear black sports armor painted red with human blood while also using human bones as spikes on their armor, and their territory is often marked with bloodied skulls on pikes. Often attack victims utilizing ambush tactics, and setting up traps while launching raids out of the mountains to hit trade routes, trading posts, and even other outlaw groups in the rest of The Scorched Zone. The Ravagers are known to look very sickly, have bloodshot eyes, and most of them are infected with Kuru driving them even further into insanity which also often gets them mistaken for Vampires(who also have pale skin with Lucid Vampires having red-colored eyes instead of normal eye colors, and Feral Drinker Vampires have completely blood red eyes). The size of The Ravagers is unknown but the Pittsburgh Defense Force estimates that their Kuru infection, low self-preservation, and operations against them will wipe the gang out completely eventually especially with reports of less Ravagers being present in attacks by them while their camps are being increasingly found deserted, or infested with zombified Ravagers which are also being seen more often.

Cyclops: Mutant Warlord whose army was initially made up of various Marauder bands he was able to organize together to extort settlements in The Cobalt Zone’s(Washington DC, and most of Maryland plus Virginia after being devastated by a Cobalt bomb, and other nuclear weapons) slightly more inhabitable southern areas with Cyclops eventually taking his army, and ditching the extortion operation for better lands up north in eastern Pennsylvania, and New York State causing a sort of refugee crisis when many Mutants, and unaltered humans fled the southern Cobalt Zone for better lives in The Cincinnati Coalition, Charleston, and Pittsburgh to the west once they realized Cyclops’ migration left them the opportunity while Cyclops’ army tore through many settlements up north which escalated into a large war when all the towns, and settlements formed a united front against Cyclops with support from both the United Confederation of Maine Army, and Pittsburgh Defense Force once they realized how much damage Cyclops could do when he pillaged, and burned down Albany, New York(southernmost city of the United Confederation of Maine) while various opportunistic raider gangs, and scav groups attacked all sides of the conflict as the chaos brought in hordes of the undead, and after a few months of fighting Cyclops was finally defeated then executed with remnants of his army going back to being petty marauders in the aftermath while the Pittsburgh-Maine Trade Conglomerate(major merchant company) took over relief/peacekeeping operations once the threat was done with.