In the grand finale of the Animorphs series, Aximili, the alien stranded on earth and seemingly forever doomed to live in the shadow of his late brother, Prince Elfangor, finally, FINALLY gets his awesome moment of crowning and is named a Prince himself and becomes a hero of his people. For the Andalites, "Prince" is a military title but the trope still counts. Particularly notable in that he went from cadet to Prince, bypassing the rank of warrior. Even Elfangor didn't achieve that.
In the Apprentice Adept trilogy by Piers Anthony, Stile ascends from the status of a serf to being a fabulously wealthy aristocrat. This happens just into the third novel rather than at the end, but it still fits the trope.
The Apprentice Rogue: To an onlooker, Artamos' formal induction to the Black Knight Order is a big to-do. All he himself can think about is how he has betrayed his king by having sex with his bride-to-be.
At the end of Barry Hughart's Bridge of Birds, the Princess of Birds is restored to her rightful place when her crown — with the feathers of the Kings of Birds back in place — is placed on her head, thus allowing her to summon the birds to create the titular bridge that will return her to Heaven.
It doesn't happen on page, but it's stated at the end of A Brother's Price that the Queens are largely retired by now, leaving running the country to the older Princesses. Once the older Princesses have had their first daughter they will outright retire and pass the titles on to their daughters — and said daughters have just married, and one of them is already pregnant.
Valraven and Varencienne's crowning at the end of The Chronicles of Magravandias combines almost all of the above instances of crowning but Standard Hero Reward. Incidentally Valraven is married to the old emperor's daughter, but that was arranged and happened seven years beforehand.
At the end of The Lion, the Witch, and the Wardrobe, all four Pevensies are crowned Kings and Queens of Narnia. This is a central plot point, as there is a prophecy saying that once the two sons of Adam (two human males) and two daughters of Eve (two human females) sit on the throne at Cair Paravel, the White Witch's endless winter will end.
We also get a good one in The Magician's Nephew wherein Frank and Helen are crowned as the first humans in Narnia, with the first of the talking animals, Diggory, Polly and Strawberry the cab horse cheering them on.
Caspian is given his rightful place in Prince Caspian. Aslan crowns him king before the Pevensies, Telmarines, and inhabitants of Narnia, before sending the children home and helping whichever Telmarines want to leave, leave.
Lloyd Alexander's The Chronicles of Prydain. Taran still hasn't found out who his parents were (and probably never will), but the High King and all his kin are leaving, and Taran fits a prophecy, so he's the new king. Aesop: Kings are made, not born (Taran probably has no royal ancestry, but has extensive experience learning how to do a good job in the role). The trope is slightly subverted by the fact that despite being "crowned", Taran has no actual crown; Gwydion very pointedly tells him that "a true king wears his crown in his heart."
In a bit of Backstory that's never directly portrayed in any of Robert E. Howard's stories, Conan became a rebel leader against the tyrannical King of Aquilonia, and eventually strangles the king on the steps of his throne. Conan then became King of Aquilonia himself.
In The Hour of the Dragon, after his brother and nephews are killed in The Plague, Tarascus gets one. He was expecting it, even though he'd been his brother's Spare to the Throne; Tarascus helped induce the plague magically, and The Plague ended with the king and prince's deaths,
Men said the gods were satisfied because the evil king and his spawn were slain, and when his young brother Tarascus was crowned in the great coronation hall, the populace cheered until the towers rocked, acclaiming the monarch on whom the gods smiled.
Lief in Deltora Quest. The Belt of Deltora is a macguffin that not only appoints the next ruler, but also keeps the Big Bad at bay. It's broken 16 years before the start of the story, and the royal family is driven into hiding. The first seven books are spent rebuilding the Belt, and the eighth tracking down the heir. Ultimately, the heir crowns himself by accident in the middle of the final battle (he didn't know he was the heir), simultaneously defeating the Big Bad.
A couple of these in the Deryni novels. In Deryni Rising Kelson's coronation is interrupted by the sorceress Charissa, who challenges Kelson's right to the crown. After much to-do, including a dramatic maternal revelation and two duels, the coronation ceremony is completed and Kelson steps into the sunlight wherein his magic destroyed Charissa's summoned monster, then has Morgan and Duncan join him there. In King Kelson's Bride Liam-Lajos Phorstanos assumes the arcane power from his ancestor's tomb. Some the ritual's participants try to seize the power from Liam and are defeated by him with help from Kelson Haldane and his uncle Matayas. Liam Mind Rips his uncle Mahael for leading the conspiracy and orders him to be impaled for his treason before ordering the ceremony to resume.
In Wyrd Sisters, the crown prince doesn't want the throne at all. The court jester becomes King when he's finally revealed to be the prince's illegitimate half-brother. The twist is, the crown prince isn't the King's son at all, but the result of the Queen's affair with the jester's father. So they are half-brothers, but the new King isn't royal at all.
Later played closer to straight in Lords and Ladies, which ends with Magrat marrying the king as planned, after almost running out and then saving everyone from The Fair Folk. Made especially awesome by the ceremony; after the elf invasion, the only suit left for the king was his old jester's outfit, while the bride wore the tattered remains of her wedding dress over the fearsome spiked plate armour she wore during her rescue of the kingdom, and the king waited to get Granny Weatherwax's approval before physically crowning Magrat.
In another part of the Disc entirely, averted thus far, where even though everyone, even people who haven't been to the city since before Carrot arrived, knows he's the rightful heir to the throne, he hasn't been made king yet. Even better, both Vetinari and Carrot know that Carrot is the rightful heir to the throne and could actually take over in a heartbeat, if he wanted to. The main issue seems to be that he has an objection to people following him simply because of that reason (in later books, he asserts bits and pieces of authority, but only as absolutely needed), and Vimes made the valid point that there are numerous problems with the term 'rightful'. After all, they (led by Vimes' ancestor) got rid of the kings and never invited them back, so presumably all of Carrot's antecedents for the last 300 years were the rightful rulers of Ankh-Morpork in their time, but it just wasn't narratively appropriate.
Vetinari practically demonstrates to Carrot that the physical throne of Ankh-Morpork, (preserved as a symbol that the Patricians are only ruling until a King returns, in which case they would be pleased to hand the job over) is so rotten with woodworm and decay that it would collapse under the weight of anyone actually trying to sit in the thing. Carrot gets the point, and remarks to Vetinari that it might be best if nobody ever got to see that.
To go along with the previous example, this trope has been perhaps been subverted the best in Guards! Guards!. The Fake Ultimate Hero that the wannabe Man Behind the Man wanted crowned for 'defeating' of the dragon was eaten by said dragon during the coronation, and the citizens decide to crown the dragon as king since, well — they still had the crown, and 'still needed a king'. When the dragon was made to leave later in the book, they went back to the Patrician, mainly because the real heir refuses to acknowledge the fact that he is the heir. Not that it didn't stop further attempts at crowning in future books.
For that matter, even in the backstory of Ankh-Morpork, it's noted that the traditional crowning process involved the King making a speech to the effect of "We hath got the crown, i'faith, and we shall kill any whoreson that tries to take it, by the Lord Harry."
Although it's rather clear that Terry Pratchett LOVES to make fun of this trope, he plays it relatively straight in Mort, where the Not Quite Dead Princess Keli bullies her faithful wizard into organising a coronation for her, which (due to unfortunate circumstances involving an elderly priest, a warp in the space-time continuum and an elephant) he ends up having to conduct himself, placing the crown on her head and ceremoniously chanting ''Iplaybetterdominoesthanyoudo' — which seems to have the desired effect!
Done completely straight in Small Gods, where the first thing the Great God Om does upon his revival is publicly declare the protagonist high priest and give him blanket permission to erase previous prophets' decrees and 'revelations.'
In Dragon Bones, Ward finally gets his title (he's not king, but his father considered the family's title better than that of king) back after lots of adventures. Played with in that, nominally, his uncle is ruling until he's of age, but people always ask him for advice, nevertheless.
In the Ea Cycle Atara (who became a Chiefess earlier in the last book) is crowned the Queen of Alonia and Valashu (who became a "plain" King earlier in the last book) the High King of the whole world.
This occurs slightly differently in The Belgariad and The Elenium by David Eddings—in each, the main character becomes royal (Garion of The Belgariad becomes King, Sparhawk in The Elenium is Prince-Consort) at the end of the penultimate book in the series (or possibly the beginning of the last one), before going off to kill an evil god using their magic rock.
Also, Garion's crowning causes a Big "NO!" on the part of his queen-to-be. See, tradition held that she (a Tolnedran princess) was to present herself in the throne room and wait for the Rivan King. If he didn't turn up in three days, she was cleared of contractual obligations and was free to return home (which was what she originally wanted). Garion's revelation as the Rivan King stunned her into a Big "OH NO!". Thankfully, she warms up to the idea, especially after Garion promises her co-ruling authority. It all works out.
One rather savvy one occurs in Guardians of the West, first book of The Malloreon. Savvy moment number one occurs when the dying Ran Borune, Emperor of Tolnedra and father of the aforementioned (by now) wife of Garion, adopts an heir: the loyal and highly-capable commander of the Imperial Legions, which means practically all the bickering and backstabbing that occurs with an heirless emperor's death is brought doubly to a halt, not only because of the named heir but also because the legions were ordered to crack down on the practices.
Savvy moment number two occurs after the emperor's death. Said general appears in the Temple of Nedra dressed not in robes but in his military armor (he later reveals this was both for image and for protection: some of the prospectives had legion training and could throw daggers)...then has himself crowned the next Ran Borune: declaring he fully intended to keep the crown. With a squad of legionnaires saluting their new emperor, any form of protest ceased forthwith.
An Elegy for the Still-living After Francis wears the fisher king's crown, the world around him begins to transform, and pulse with vibrant life.
Subverted in Elminster: Making of a Mage. Elminster Aumar is the last rightful prince of the Stag Throne. After wresting it from his uncle, the Magelords standing behind the throne and apparently an undercover malaugrim riding evil dragon playing puppetmaster, Elminster gives the crown away to the last faithful knight of his father's throne before riding off into the sunset.
David Weber's Empire from the Ashes series has two. The first comes in the first book when Dahak (also known as the Moon) promotes Colin MacIntyre to be his new captain. Talk about Cool Starship. He later promotes himself to Governor of Earth in order to exploit a clause of Imperium law. The second comes in the next book when Colin unintentionally crowns himself Emperor when he orders Battle Fleet's central computer to implement "Plan Omega" so he can get the information he needs without allowing Dahak to read him the fine print.
In Lois Lowry's Messenger, the 'sequel' to The Giver, it is indicated that Jonas, the hero of The Giver, is somehow made Leader of the new Community, despite having just been a thirteen year old kid on a sled when he arrived.
Gormenghast: In Titus Groan, one-year-old Titus subverts this trope when he drops all three ceremonial objects that tradition obligated him to carry at his Earling into the lake.
What happens when you win the game in Heir Apparent. Then the world dissolves in a shower of glitter.
Heralds of Valdemar, Mage Storms: As related in a flashback during Storm Warning, the beginning of Solaris' episcopate can best be described as memorable. During a mid-winter solstice high holy day ritual at the main temple of Karse, the prior Son of the Sun made a ritual invocation in the name of Vkandis Sunlord... and was answered. Among a number of other Signs and Portents (the summary incineration of the incumbent being among the less unsubtle) a seated monumental statue of Vkandisnote (carved from a solid block of stone) got up, removed its crownnote (part of the statue) shrunk it down, and set it on the head of the priestess/mage Vkandis wanted for the job. Most of Karse and the bulk of the Sunlord's priesthood took the hint.
In The Hunger Games, the Victor of each Hunger Games is ceremonially crowned by the President of Panem in a public ceremony. In-Universe, it's a moment of celebration and joy, but bitter-sweet for the tribute, as it usually means that their District partners, allies, and friends in the arena perished.
In Garth Nix's Keys to the Kingdom series, Arthur becomes the New Architect the moment he finally brings the Will together, and gets to remake the entire Universe from scratch. He even gets his own 'Let there be light' moment.
In The Wonderful Wizard of Oz the Scarecrow takes the Wizard's place ruling over the Emerald city because the Wizard said so, the Tin Woodman gets asked by the Winkies to lead them and eventually accepts; and finally, the Lion becomes King of a forest full of animals when he defeats a Giant Spider.
In The Marvelous Land of Oz the protagonist, a boy called Tip, is crowned ruler of Oz. This is because he is revealed to be the rightful ruler of Oz, Princess Ozma, transformed into a boy when a baby, and Glinda forces the witch Mombi — who transformed him to begin with — to turn him back into a girl.
And then in Ozma of Oz, the third book, Ozma meets Dorothy Gale, who is making the first of many return visits to Oz (before finally moving there outright). They become instant best friends and Ozma declares Dorothy to be a Princess of Oz.
The Tribulation saint martyrs are given one by Jesus Christ prior to the start of the Millennium in the Left Behind book Glorious Appearing.
Aragorn is crowned King of Gondor after the defeat of Sauron, in a wonderfully awesome ceremony, lightened by gossiping asides by bystander Ioreth in the watching crowd.
Éomer becomes the king of Rohan on the battlefield when Théoden dies. The actual coronation ceremony isn't depicted, but happens after the war is done.
At the end of Tad Williams' Memory, Sorrow, and ThornDoorstopper trilogy, Simon Snowlock is crowned King. Although the moment is not particularly awesome, per se, as the land he's make King of has been fairly well wrecked.
Deconstructed in The Neverending Story, Bastian has gone insane with arrogance and decides to take Fantasia for himself, so he decides to be crowned as new Childlike Emperor. The book depicts the scene with strong music, but monotone. People were forced to dance and jump to it. Buildings were decorated with flags and banners with bright colors, but there was no wind to move them. And everywhere they could see portraits of Bastian's face. The depiction of the whole scene makes it sound pretty awkward.
In Garth Nix's Old Kingdom trilogy, the long-lost prince is first discovered as a Human Popsicle, and reluctantly reveals his heritage (he was the bastard son of the ruling Queen and the only survivor of the royal family). When we revisit the Kingdom fourteen years later, he is definitely King and married to the heroine from Book One.
The last chapter of the fourth book of the Empire of Man (or Prince Roger, after the main character) series, co-written by David Weber and John Ringo. It's also a good example of a Chekhov's Gun, since Prince Roger starts out in the first book as a Royal Brat. The scene in question can also can serve as a Tear Jerker, in regards to the fate of Empress MacClintock.
A Conspiracy of Kings, the third book of The Queen's Thief, sees Sophos finally face his destiny as the heir to his uncle, the late king of Sounis. To actually be crowned as king with no regent, he must convince the barons that he's the right man to end the civil war tearing up their rather cynical nation. Sophos first tries to appeal to reason and the greater wisdom of pledging loyalty to Attolia, which will help the whole peninsula repel The Empire. This falls flat. Sophos makes his second argument: pulling out a pistol and shooting the head of the conspiracy to turn him into a Puppet King, in full view of the entire amphitheater. The barons' subsequent second vote confirms him unanimously.
Redwall: At the end of High Rhulain, Tiria is crowned High Rhulain, Queen of the Otters. Though this has been seen as Narm by many fans.
At the midway point of the Revanche Cycle, Livia is crowned the first female pope in history — a triumph made possible by extensive social engineering, skilled propaganda, a murder or two, and a pledge to instigate a bogus inquisition to further King Jernigan's own ambitions. Bonus: she then immediately dispatches her fanatic bodyguards to screw with Jernigan's plans, taking back her own authority.
Magician, the first book of Raymond E. Feist's The Riftwar Cycle, ends with an unusually tense one. Lyam and Arutha, both noble sons, find themselves with a Field Promotion after the King, their own father and every other noble standing between them and the crown die in battle (actually that was it — the only other person between them was their uncle who died of a prolonged sickness before then). The complication comes when it is revealed that their father's chief ranger, Martin Longbow, is their father's bastard son and, by virtue of his age and their father's deathbed acknowledgment, the rightful heir to the throne. This at a time when the country is already on the brink of civil war and half the nobles are looking for any excuse not to acknowledge the named heir (Lyam) for political reasons.
At the end of Patricia C. Wrede's Shadow Magic, Alethia is crowned queen of Alkyra largely because she had managed to survive wearing the crown (a long-lost magical artifact), and was acknowledged as the rightful heir when she had done so. Afterward, she defied her advisors by insisting on marrying the man she wanted, and on being crowned in the middle of Starmorning Field where everyone could see her rather than making enemies by picking and choosing attendees for a smaller site.
In George R.R. Martin's A Game of Thrones, the first volume of A Song of Ice and Fire, Viserys finally gets the crown he's been badgering Khal Drogo for. Unfortunately for him, it's made of molten gold, is the size of a barrel, and is poured down his throat and all over his face.
Played straight at the end of the same book when Robb Stark reclaims the ancient title of his House and is proclaimed the King in the North (aka The King Of Winter).
Gerald Morris' The Squire's Tales: Lampshaded in Parsifal's Page; the titular Parsifal gets crowned mid-beginning of the story, which leads to the main character, Piers, commenting on how that sort of thing wasn't supposed to happen until AFTER the story ends.
At the end of Howard Weinstein's Star Trek: The Original Series novel The Covenant of the Crown, the rightful heir proves her identity to the crown's guardians by putting on the crown and successfully controlling the crystals set within it. (This was in effect a Secret Test of Character arranged by her father.) The actual coronation on her home planet is also shown later in the epilogue.
Sword at Sunset: Artos, Heroic Bastard commander of the allied British, is acclaimed Caesar by his victorious, drunk troops in an inebriated mashup of Roman and Celtic, Christian and pagan rites on the eye of the White Horse of Uffington after the Battle of Badon Hill.
Averted in Terry Goodkind's Wizard's First Rule, the first book of The Sword of Truth. Richard kills his father, Darken Rahl, but doesn't know about the family connection. Everyone bows down before him and salutes him as Lord Rahl, and he just kinda figures that it's a thing of respect or something and takes his leave, muttering "I'm just a woods guide."
In Ann Maxwell's Timeshadow Rider, the Kiriy of Za'ahrain — the ruler of the planet — is the first person who, upon the death of the previous Kiriy, can survive wearing the Eyes of Za'ahrain, which are effectively a crown that is also a magical artifact used to keep the inherent violence of the people from surfacing in the present time. The Eyes are stolen upon the death of the Kiriy at the beginning of the book, and are pursued by the protagonists (who are the two most likely to survive attempting to wear them) throughout the book, although neither wants the job. Subverted in that when the Eyes are finally retrieved and the protagonists are facing up to seeing who will be the next Kiriy, their Mons, sensing that their human partners don't want the Eyes, promptly make the Eyes permanently disappear.
Prince Jonathan is crowned near the end of Song of the Lioness. It's pretty spiffy — placing the crown on his head magically binds him to the kingdom. (Something like that.) Unfortunately, it's also the moment the Final Battle begins, thanks to Duke Roger and his rebels.
Dovasary Balitang is crowned after the raka revolution succeeds in Trickster's Queen. After centuries of oppression, a thoroughly capable raka/luarin queen takes the throne at thirteen, putting the crown on her own head as is traditional in Kyprish coronations (since no one wants to offend their patron god by claiming his priesthood).
In The Voyages of Doctor Dolittle, this happens when he is crowned King of Spider-Monkey Island, despite not wanting to be a King. The shouts from the people are so loud they topple a stone which causes the moving Island they are on to stop moving.
Warrior Cats: No actual crown involved, but Firestar's leadership ceremony would probably count.
So does Bluestar's, especially after reading an entire book about all the crap she had to get through to become leader in the first place. Leafstar's might count as well.
And every single leader who came before and after them. Ditto for the warrior ceremonies.
The climax of the Werewolf: The Apocalypse novel The Silver Crown, in which the crown is a legendary artifact that fries the heads of the unworthy and becomes Albrecht's last hope for mounting a credible challenge to Arkady, who'll become king otherwise (and who set up the death of Albrecht's grandfather, the last one). It finds Albrecht worthy, whereupon he's healed from recent injuries — including being skinned alive (thankfully, Samuel Haight was not involved) — and uses its powers of ordering-people-around to get rid of all the remaining enemies in the room — including Arkady, who he exiles. His formal coronation comes afterward.
No crown involved, but in The Wheel of Time, Egwene gets a good one after she reunites the tower, and becomes Amyrlin for the whole Aes Sedai. Immediately after, she makes a speech telling the sitters that they're a disgrace for allowing Elaida to nearly destroy them all.
Subverted several times with Rand (sometimes he isn't even literally crowned), Perrin (sort of, at the end of "The Shadow Rising" when he is acclaimed as Lord Perrin the Golden-Eyed), Egwene (when she is raised as Amyrlin at Salidar) and now Tuon too, as the event comes together with new duties and troubles.
Rand does get at least one crown, but his coronation (if he had a proper one) is not shown.
In Oscar Wilde's short story The Young King, the title character refuses his regalia on his coronation day after a series of dreams shows him the suffering of those who produced it. Instead, he dons his old shepherd's garb and a crown of thorny branches he weaves himself, then takes up his old wooden staff and goes to the ceremony. Furious nobles threaten to kill him in the cathedral for bringing shame on the kingdom, but sunlight causes the staff and the crown's branches to come to life and flower while the garb glows as if golden. The would-be assailants are humbled and the bishop cries out, "A greater than I hath crowned thee!"
, once Thistledown completes his Fetch Quests and becomes a much humbler elf, he releases his girlfriend Lilybell from the enchanted sleep she has been put in by the Brownies. This trope follows immediately afterwards, with the Brownies crowning the two as the King and Queen of the local fairies.