Based on their motives:
* Raiders: This is a more neutral term, simply suggesting they take what they want by force.
* Prowlers: Implies stealth and cunning, perhaps lurking in the shadows.
* Reavers: Conveys a sense of ruthlessness and destruction.
* Scourers: Suggests a more widespread and systematic looting of resources.
* Despoilers: Emphasis on taking something precious and leaving behind devastation.
* Extortionists: Focuses on their use of threats and intimidation to gain resources.
* Preytakers: Highlights their predatory nature and their targeting of specific individuals or groups.
* Black Marketers: Implies they operate outside the law and traffic in stolen goods.
Based on their tactics:
* Infiltrators: Focuses on their ability to penetrate defenses and move unseen.
* Sabotageurs: Emphasizes their use of destructive tactics to disrupt or disable.
* Ravagers: Conveys a sense of chaotic and brutal violence.
* Mercenaries: Implies they are hired for their skills, not driven by ideology.
* Assassins: Focuses on their use of stealth and lethal force.
* Renegades: Suggests they are former members of some established group who have gone rogue.
* Outcasts: Implies they are ostracized and operate on the fringes of society.
Based on their origin/culture:
* Nomad Clan: Implies a nomadic people with a strong sense of community.
* Renegade Collective: Suggests a group of individuals who have united against a common enemy.
* Shadow Syndicate: Conveys a sense of mystery and secrecy.
* The Scourge: A more ominous and powerful title, implying a widespread threat.
* The Crimson Hand: A more evocative and memorable name, with a strong visual impact.
Other options:
* Reavers (from Firefly)
* Wraiths
* Harbingers
* The Unseen
* The Shadows
* The Whispers
Ultimately, the best terminology will depend on the specific details of your marauders and the overall tone of your science fiction novel. Consider what aspects of their character you want to emphasize, and choose a term that reflects those qualities.