The City of Dreaming Books

"But what was the point? I demanded, sitting up with a groan. I nearly went mad, I didn't understand any of it, and I've as good as forgotten it all again."
"It's always the same with demanding literature."

The City of Dreaming Books is a fantasy novel by German author Walter Moers. It's a tribute to books and reading, but also chock full with Lampshade Hanging and tropes of all kinds.

The novel takes place on the fictional continent of Zamonia, which is populated mainly by anthropomorphic animals or other types of imaginary creatures. The story follows Optimus Yarnspinner. Optimus is a Lindworm, and like all of his species, he is destined to become a writer. When Optimus' mentor Dancelot dies, he leaves Optimus his most valuable possession: the greatest manuscript ever written. After reading it, Optimus becomes determined to meet the unknown author, and sets off for the city Bookholm in search of him. Bookholm is a city dedicated entirely to books. The city itself is filled with bookstores, publishing houses, and writers, editors, publishers and critics. Bookholm also sits atop a huge expanse of catacombs, which are filled with the rarest books in existence, as well as large numbers of dangerous creatures. Bookhunters are employed to find books in the catacombs, and the books are so valuable that Bookhunters often resort to boobytraps and murder to get them. In all of this, Optimus begins to search for his mysterious author, but quickly discovers that his quest is more dangerous than he had anticipated.

Tropes used in The City of Dreaming Books include:

Absurdly Spacious Sewer: The catacombs have traits of this.
Ancient Tomb: Under the city streets lies a vast networks of tunnels and vaults, filled with old books.
Awesome McCoolname: Colophonius Regenschein.
Arc Symbol: The Triadic Circle for the Part One of the book.
Badass Bookworm: Colophonius Regenschein, the most famous Bookhunter in the city.
Body Horror: The story of The Shadow King.. Oh so much so.
Bounty Hunter: The Bookhunters could be taken straight out of Star Wars, except that they hunt books.
Dark Is Not Evil: The Shadow King.
Dead Person Conversation: Possibly. Optimus is never clear whether he actually talked to the ghost of his mentor Dancelot, or if he imagined it, since he was pretty close to insanity at that point. Either way, it helped.
Eldritch Abomination: A variation with the scientist giant.
Evil Counterpart: Rongkong Koma the Terrible to Colophonius Regenschein. They're both highly successful Bookhunters, but while Regenschein finds rare books by using his wits, Rongkong Koma is the most violent and deadly Bookhunter in the catacombs.
Fate Worse Than Death: It's implied that Smyke wants to turn Optimus into the new Shadow King.
Genre Blindness: Discussed by Optimus, when he finds himself standing at the entrance to a spooky castle, and reflects that if he were the hero of a horror story, he'd walk right into the castle without a second thought. Although, as it turns out, Optimus himself isn't quite Genre Savvy enough:

Not me though! I wouldn't go inside. . . I wasn't some asinine hero who risks his neck to satisfy the vulgar requirements of a lowbrow readership. No, I wouldn't go right inside, I would only go a little way inside. Where was the harm in that, after all?

Haunted Castle: Big time.
Heroic Sacrifice: Colophonius Regenschein, who is already dying, kills himself so that others won't endanger themselves by staying behind to protect him.
He Who Fights Monsters: Homuncolossus becomes the most terrifying thing in the catacombs by killing Bookhunters, until he has a My God, What Have I Done? moment.
Heterosexual Life Partners: Homuncolossus and Optimus Yarnspinner. They get... very close, very quickly, sometimes bordering on Ho Yay.
Hurricane of Puns: Pick a name. Any name. Often mixed with a certain degree of Genius Bonus.
I Have This Friend: A particularly dark example with Homuncolossus.
Ironic Echo: If it lives, it can be killed.
It Gets Better: In-universe. The protagonist was told repeatedly by his uncle to read the great novel "Ritter Hempel" (Hempel the knight), but gave up after the first fifty or so pages were all about how to clean lances. Only later he learns that everyone else had the same problem, and later in the book there are great and funny scenes, like when the knight loses his glasses in his armor.
Just Between You and Me: The Big Bad loves this. So much so that he tends to jump the gun, telling his evil plan to people who don't even realize he's evil. Then he disposes of them.
Lampshade Hanging: Happens a few times, often with some Hypocritical Humor thrown in. The characters will mention a trope that is occurring, and point out that such tropes only occur in works by hack writers. For instance:

Dancelot (on his deathbed, about to make a sensational revelation): The last words of a dying man on the point of imparting a sensational revelation! Make a note of that literary device, it's a guaranteed cliffhanger! No reader can resist it!
Optimus (narrating): Although Dancelot was dying, nothing seemed more important to him at that juncture than to teach me a cheap trick favoured by trashy romantic novelists.

Literary Agent Hypothesis: This is (the first part of) Optimus Yarnspinner's autobiography, which Walter Moers merely translated.
Mad Scientist: Smyke, the giant, and the alchemists referenced several times throughout the book.
Meaningful Name: Optimus Yarnspinner, who is going to be a writer. Since his entire species is writers, the meaningful name isn't that surprising.
Mind Control Device: Trombophone music. Not only can it induce powerful hallucinations, but it can also plant suggestions that linger for some time.
Painting the Fourth Wall: Used when Optimus Yarnspinner passes out. First, when he opens the poisoned book, the pages of the novel turn into the pages of that book. While he is losing consciousness, the page is black with white type. To give a sense of time while he is passed out, there are a few pages with no text, just blackness or illustrations.
Poor Communication Kills: Two different people warn Optimus that he is in danger and must leave Bookholm at once. Neither of them, however, explains why, beyond a few cryptic warnings.
Ridiculously Cute Critter: The booklings.
Sand Worm: The "victorious worm", with a bit o' Worm Sign thrown in for good measure.
Schmuck Bait: Pfistomel Smyke poisons his victims by handing them a book, and telling them to open it to a certain page. And bear in mind, he does this after the victim knows perfectly well how evil he is.
Serious Business: Books. People will die for books. People will kill for books. People will kill with books to get other books. Optimus Yarnspinner's entire species is made up of writers, and there are other species in existence who dedicate their lives to books, even one that feeds off of reading.
Shout-Out: Many of the names of authors and some of the poems recited are anagrams of the names of real life poems and authors. For instance, the author Doylan Cone comes from Conan Doyle, and the poems of Edgar Allan Poe and Shakespeare show up as well.
Take Our Word for It: The manuscript. Everyone who read it said it was probably the greatest piece of literature ever written, to the point where its mere existence endangered all of fiction, because after reading it, no one would ever be satisfied with a something less perfect.
Taking You with Me: Homuncolossus to Pfistomel Smyke, with a bit of Driven to Suicide thrown in as well since Homuncolossus wanted to feel sunlight one more time, even though he knew it would kill him.
The Brute: Rongkong Coma.
Tragic Monster: Homuncolossus, and how.
With Great Power Comes Great Insanity: It's shown that from an early age Homuncolossus wasn't a perfectly stable person. But being turned into a gorilla shaped paper monster and left in an inescapable labyrinth prison did not help his state of mind in the slightest.
Weak but Skilled: Colophonius, contrasting with Unskilled but Strong Rongkong Coma.
Wretched Hive: Many parts of Bookholm appear to be this.