Anyone Can Die: One of the 'Principles' for MCs is 'Look Through Crosshairs,' which essentially translates to this. And NPCs die VERY easily.
Asskicking Equals Authority: As a general rule. The Chopper and Hardholder classes even have moves allowing them to use their Asskicking stat (Hard) to exercise their authority.
Badass Crew: The Operator class' whole shtick is that they run one of these. Although if it's made up entirely of NPCs, they die as easily as anyone else.
Class Change Level Reset: One of the advanced level-up options is to have your character change class, which involves giving up everything that ties them to their current class (up to and including leadership of a settlement).
Combat Medic: The Angel class can easily be this. One of their moves gives them extra armour when they are healing people.
Continuing Is Painful: When a player character is very badly damaged (and probably unconscious), they will just keep taking damage until they die, unless they're saved by another player...or they can take a Debility, which permanently reduces one of their stats by one point (a significant amount when stats only go up to three).
The Face: The Skinner class fits perfectly into this, as they're all about social interaction. They even have an ability that can make NPCs unwilling to act against them, which is pretty remarkable in a setting like this.
The Faceless: The Faceless class. If their mask is removed, it's always treated as The Reveal, stunning everyone nearby and freaking the Faceless out, with varying negative effects.
House Rules: The system is notably designed to be hacked into other games and settings. Oddly enough, there are no less than three published hacks (including one by the designer) for Urban Fantasy games.
Human Popsicle: The Quarantine class. They get a base full of wonderful stuff, but they don't understand the culture and they aren't prepared for the damage The Maelstrom can to one's psyche.
Level Up At Intimacy +/-4: When your Hx with another character hits either top or bottom, it resets to almost neutral and you get experience.
Made of Iron: The Gunlugger and the Faceless tend to be this. The Gunlugger, notably, can take a move making them as tough as a small group of people.
Mask of Power: The Faceless' mask can be played as this, depending on which moves they have and whether they lose them without the mask.
Mind Rape: The Brainer class (psychics, essentially) can start with an item that allows them to do things which normally require 'time and intimacy' with simple skin contact. It's called the ''Violation Glove'' .
No Experience Points for Medic: Completely averted by the Angel, the designated medic playbook: if anything, they have the potential to gain more XP than anyone else, because for every point of harm a PC (read: Angel, because no one else really has healing abilities) heals another PC of, the former gains Hx+1 with the latter, quickly maxing out and resetting Hx for bonus XP.
No Sell: The Battlebabe's special sex move automatically cancels out any sex move their partner(s) may have.
One Stat to Rule Them All: Cool and Sharp both have this reputation. The other three stats apply to fairly specific situations (Hard is for hurting or threatening people, Hot is for persuading people, and Weird is for going on bizarre psychic dream-quests), while Sharp gives you bonuses to any other roll as long follow the MC's advice, and Cool is for almost EVERYTHING else.
To a lesser extent, one can build one's character to make this the case for whichever stat they prefer, so that they (for example) roll against Weird whenever they would normally roll Cool.
Plot Armor: The "looking through the crosshairs" principle the MC is required to follow generally means that any NPC may be offed with no build-up at any time. There are two exceptions to this, however: a PC who has been retired to safety via an advanced improvement and an NPC who has been turned into an ally via a 12+ roll on the advanced Seduce or Manipulate move. They are (mostly) safe from the MC's capriciousness.
Psychic Dreams for Everyone: The Psychic Maelstrom functions a bit like this: one of the basic moves (things any class can do) is to 'Open their Brain' to it and get psychic answers about whatever they want, often in a completely baffling way.
Relationship Values: Every PC has a 'History' stat for every other PC, which indicates not their feelings towards that character, but rather how well they understand them. This stat is rolled against whenever a player wants to help (or hinder) another's roll. It's initially set by choosing options during character creation which determine certain feelings or past events (the Faceless thinks someone is pretty, and someone once helped them do something nasty, for example).
Religion Is Magic: Mostly religion is people worshipping water, machinery, or Abe Lincoln, but it is possible for the Hocus class to play this somewhat straight, notably with a move that gives them armour (as long as they aren't wearing any other armour) with no real explanation other than 'from the gods.'
You Bastard: From the Operator's playbook no less. The Operator can have a move to interfere with people's action by rolling for Cool, the playbook comments by calling the player out as an asshole for taking this literal dick move.