Ambiguous Disorder: The Toymaker is by his own account not neurotypical and relies on meds to maintain the control his job requires. When those meds are unavailable he demonstrates symptoms of a schizophrenia type disorder.
Arson, Murder, and Jaywalking: During the book's climax, one criminal is arrested for a wide variety of crimes including tax evasion, the production and sale of various illegal items and substances, and so on, and as an afterhthought, sneaking mis-labeled bread mix into Scotland.
Asshole Victim: The victims are all criminals, for starters. The first one is a bulk spammer who was previously convicted for selling fake medication online. Another one was a money launderer. Starts to get a bit greyer later in the book, when more sympathetic characters such as Tariq start getting murdered as well.
Axe Crazy: John Christie. He is at least taking medication to keep the worst of it under control. According to his backstory, it's In the Blood.
Nope, it's not. While both are psychopaths, John picked up his schizophrenic symptoms from a less-than-successful treatment with psychopharmaca during his childhood.
Played for Laughs later, when Anwar gets a phone call that puts him on edge, and when he looks around for signs of anyone following him, is told by the voice on the other end of the line to stop doing that, because he's drawing attention.
Chekhov's Gun: The bread mix, which is not only bread mix. Used with the right activating agent, it can be used to mass-produce spider silk. Used without the right activating agent, it can also be used to make crappy beer.
The Chessmaster: Colonel Felix Datka, working under the orders of his boss, the President of Kyrgistan. And he is yet another Unwitting Pawn of ATHENA. It just so happens that his goal and hers are compatible.
Cowboy Cop: Discussed and Dismissed. It is widely acknowledged that modern police work is about managing large groups of personnel doing quite a bit of seemingly pointless tasks working towards a common goal.
Corrupt Corporate Executive: It is widely agreed that they were to blame for the economic collapse of the early 21st century. John Christie is also this after a sort. A psychopath (er... make that Neurodiverse individual) who was recruited and given top-quality business schooling to produce the perfect sociopathic businessman.
Death from Above: A few references are made in passing to Americans launching Attack Drone air strikes on troublesome individuals, but one Ameican official insists that they aren't in that business anymore.
Everything Is Online: Very nearly literally true. Late in the book, a military unit launches a raid to arrest various individuals, and one of their preperatory steps is to have every soldier turn off and lock up their radios, cell phones, computers, etc. before leaving base, effectively making them disappear from the net entirely until they get to their destination.
Gone Horribly Right: ATHENA was designed as an AI that would use social engineering to nudge individuals showing a high chance of becoming criminals away from a life of crime, or to sniff out spam botnets and identify them for the authorities. Instead, ATHENA is nudging criminals and law enforcement agents into confrontations with each other, and arranging for unlikely deaths-by-chance of various criminals.
Hidden Depths: Anwar is stunned to discover that his wife is much more familiar with his dealings than he realized, knowing, for example, what the going price is for the Issyk-Kulistani bread mix that he's been a mule for on the Black Market. Being familiar with criminal doings is not the same as approving of them, as Anwar discovers when he is banished to the couch for asking her to go into business with him.
Ironic Echo: Played for narrative humor a few times, when various paranoid characters fuss about the police recon drones that are no doubt watching what they do, or dismissively claim that they are just being used to enforce anti-littering ordnances. Once the narration switches to Liz's perspective, it mentions the omnipresent police recon drones, which mostly get used to look out for people littering, as a means of justifying their cost.
How Many Fingers?: Liz to Kemal, after he gets knocked down a flight of stairs by Christie. After Kemal has to think about it for a few seconds, Liz tells him to wait for the ambulance.
Make It Look Like an Accident: ATHENA's Modus Operandi: Set up a great many circumstances where an accidental death is possible, and wait for random chance to take effect. Defective replacement parts for appliances, mis-labeled or contaminated medication, etc.
Memetic Mutation: In-Universe, Liz's squad is responsible for searching the internet for memetic crime. Thanks to the interconnectness of the world, copycat crime is a huge problem.
Mission Control Is Off Its Meds: The Toymaker begins to suspect this towards the end. It is left unclear whether ATHENA broke into The Operation's network, whether he's becoming increasingly paranoid due to having the wrong medication, whether he's been talking to ATHENA all along — or *all of the above*.
Not So Different: Kemal and Liz, who were antagonistic towards each other in Halting State, now find themselves both working together after having their careers derailed by the events of Halting State.
One Degree of Separation: All of the crimes, and ultimately all of the important characters, are tied together by seemingly random coincidence. Lampshaded by the increasingly frustrated police officers because coincidences don't happen that often. Both the cops and the villain realize by the third act that they are being "nudged" towards a confrontation with each other.
P.O.V. Sequel: Liz Cauvanaugh, the high-and-mighty Detective Inspector that Sue was working for in Halting State, is now a main character suffering from a bit of burn-out.
Pragmatic Villainy: John Christie is a psychopath who sees other human beings as being effectively disposable. However, he also knows that drawing undue attention to himself is bad for business, so he goes out of his way to keep a low profile.
The Purge: ATHENA uses John Christie and other unwitting pawns to eliminate the humans involved in its creation.
Reassigned to Antarctica: Liz's fate after the events of Halting State, she has spent the last five years heading up the Innovative Crime Investigative Unit, known as the Rule 34 Squad, which specializes in trawling the internet for crime-related memetic mutation, which means they get to dredge through all the worst the internet can offer them. The ICIU tends to be a dumping ground for any cops who don't mesh well elsewhere in the force.
Kemal as well, after his actions in the same book.
Sanity Slippage: The Toymaker experiences this through the course of the book ( but that's just what the lizards want you to think). It might be due to a bad batch of medication courtesy of ATHENA.
Theme Naming: John Christie's alias happens to be the name of a prominent serial killer from the previous century. When he gets a new alias issued to him, that one turns out to be the namesake of another serial killer. He is not amused by this and suspects that an outside party is tampering with the Operation's system to make him stand out more.