Consider Phlebas is the first Iain M. Banks novel set in The Culture. It concerns the war between the Culture and the Idiran civilization, an event whose repercussions affect all of the future novels in the series. Interestingly, the novel is mostly told from the perspective of Bora Horza Gobuchul, a "Changer", who sides with the Idirans and sees pretty much all of the Culture's signature aspects in a highly negative light.
Consider Phlebas provides examples of the following tropes:
All for Nothing: Every damn escapade Horza gets his team involved in ends in disaster. Yet still he won't quit while he's behind.
Anti-Hero / Anti-Villain: Horza is the former in respect to the novel, but could be seen as the latter to the extent that the Culture itself is the protagonist of the series.
Death World: An unseen example is the Idirian homeworld, which has caused them to evolve into Badass warriors. The planet where the lost Mind is hiding is something of a literal example, being a world that once evolved sentient life with an advanced civilization until said life wiped itself out in the culmination of something like our Cold War.
Dead Person Impersonation: At the opening of the novel, Horza has been exposed impersonating a politician for the Idirans; once he's picked up by Space Pirates, he makes plans early on to replace the Captain, and eventually does.
Determinator: Quayanorl suffers mortals wounds and is left behind. Gruesomely injured, blind, and dying, he still manages to drag himself to perform one last action against his enemies, which averts the impending happy ending and turns it into a kill 'em all.
Inside a Computer System / Cuckoo Nest: Horza is knocked out and dreams that he's woken from an immersive computer game. The technician tending to him gets some of the details of his story wrong, and when Horza tells him so, the guy realises he's woken up the wrong person and puts him back under. Horza wakes up, and none of this is ever mentioned again.
Fantastic Racism: Horza hates and despises sentient machines (to be sure, he doesn't believe they're really sentient). Most Idirans despise non-Idirans (see Superior Species), and they have a religious justification for it.
Xoralundra: Whoever heard of a mortal creature with an immortal soul?
Gang Initiation Fight: Horza is forced into this when picked up by the Space Pirates, but it turns out that it was something of a ploy on the part of the pirate captain, who wanted to get rid of the guy Horza was fighting.
Kill 'em All: Horza, Yalson and the rest of the Clear Air Turbulence Crew, and the Idirans all die in the finale, and the drone Unaha-Closp is babbling nonsense and nonfunctional from damage. Perosteck Balveda makes it out alive, only to have herself put into suspended animation and then commit suicide as soon as she is revived. The only aversion is that Unaha-Closp is repaired later before eventually merging into a collective.
Nice Job Fixing It, Villain: The Idiran special forces team led by Xoxarle is so xenophobic, stupid and singleminded that they betray the Free Company, get pretty much everyone killed, and leave Balveda able to rescue the Mind that would otherwise be theirs. To an extent this is also reflected in their overall conduct of the entire war — while they never had a hope of actually winning, they could have got out while they were ahead, or conducted their campaign much more efficiently.
Xoxarle, who — after Horza and company capture him following a Ray Gun fight — spews insults at the Changer in a futile attempt to get himself killed and reunite with his fallen comrades, rather than face the shame of being taken prisoner.
Quayanorl, Xoxarle's comrade, despite grievous damage done to him during the aforementioned lasergun fight, manages to drag himself up to the train parked in the station, get it running, and wham it into the train sitting in the station Horza and the others are occupying, kicking off the cataclysmic fight that gets everybody but Balveda and Unaha-Closp killed. The Idiran fulfills his wish to die having contributed nobly to his species' cause.
Rock Beats Laser: Armed with laser weapons, the Space Pirates attack an old temple located in a non-spacefaring civilization, defended only by monks with primitive firearms. See Temple of Doom below. About half the company is wiped out in the resulting chaos.
Scary Dogmatic Aliens: Seemingly the Idirans, but the appendices reveals this as an inversion. The Culture is willing to fight to the last against a civilization that is no physical threat to them based on ideology alone, while Idirans want to cut the war short with a political settlement.
Shapeshifter Identity Crisis: Horza (as a shapeshifter) has a literal invocation of this trop. He doesn't lose control of his shifting, but several of the dream sequences he experiences hint that he may not actually be who he thinks he is.
Shoot the Shaggy Dog: Horza dies, everyone his ship dies except for the drone and Balveda. Balveda rescues the damaged Mind that Horza was attempting to retrieve. A post-war report at the end of the novel then goes on to say that Balveda later offs herself, and that Horza's species (the Changers) ceased to exist as a species.
Snarky Non-Human Sidekick: Unaha-Closp. Throughout his tenure with Horza he becomes the Butt Monkey of the gang, being ordered about to perform the dirty work (perhaps due to his high practical utility as a sentient drone). Despite his cynical attitude towards Horza's endeavors, near the end he prevents Balveda and Horza from being mauled to death by Xoxarle.
But only at first glance. She's as competent as anyone else and doesn't die because someone wants to torment someone else. She gets killed because she is herself considered an enemy.
Superior Species: Thanks to evolving on a Death World, Idirans are practically immortal and indestructible; also, the Changers' shape-shifting and poison claws are definitely a product of some intricate genetic engineering. In the end they are utterly crushed by the Culture: the Space Hippies might seem to be hopelessly outgunned by the Idirans at the beginning of the novel, but that's only because they have not even started to fight back yet. Being physically superior than pan-humanity as individuals just doesn't go that far in a high-tech galactic war. Especially when they have AIs running the show with brains so large they have to use Hyper Space for data storage. This is actually why Horza sides against the Culture, he doesn't trust the machine minds, and sees them as a threat to the galaxy as a whole. He thinks the Idirans are pretty damn superior, but still just another empire like all the others from history. Idirans are able to fight the Culture on pretty impressive terms in space as well (winning even one battle with the Culture is not to be sneezed at), indicating that they must have incredible natural reflexes and multitasking capabilities.
Sympathetic P.O.V.: Horza hates the Culture and, for example, while the later novels draw humor from the humorous/macabre names the Culture gives to ships, he's disgusted by this apparent display of the Culture's cavalier attitude towards something as grim as interstellar warfare.
Temple of Doom: The Temple of Light; it's constructed from crystal blocks that turn shots from laser weapons back on the shooter, among other tricky defenses.
This Was His True Form: Balveda has a moment invoking this trope as she takes Horza's corpse with her off the planet at the end, reminiscing that for all their interactions, this is the first time she has seen his real face.
The Idirans possibly appeal less to the reader being of terrifying and nonhumanoid appearance. Homomda, who at the time were a shade ahead of even the Culture, had assisted the Idirans in the past at least partly because of their shared tripedal ancestry, and even supported them for a time during the Culture-Idiran War. Once you really get to know the Idirans things don't improve over the first impressions.
Unaha-Closp plays a vital role at the end of the novel, contrary to Horza's implicit discrimination against the drone.
Worthy Opponent: Horza and Special Circumstances agent Perosteck Balveda to each other. Horza reminisces that they've both been in situations where one was about to die and the other didn't help, but when push comes to shove they're not keen on actually killing each other.