At the end of The Hunchback of Notre Dame, they find Quasimodo's skeleton so intertwined with Esmeralda's that when they try to remove it, it falls to dust.
In The Mill on the Floss, Maggie and her brother, previously estranged, embrace each other as they drown.
The fantasy novel Bridge of Birds has no fewer than three couples thus reunited.
Inversion: The Scarlet Letter makes its point more poignant by emphasizing the fact that Hester and Dimmesdale's graves, though near each other (and even sharing a single tombstone), were not touching "as if the dust of the two sleepers had no right to mingle".
Combined with Ironic Hell in The Divine Comedy— the illicit lovers Paolo and Francesca di Rimini embrace in Hell, but according to the usual interpretation, their union serves as an eternal reminder of their sin rather than a continuation of true love beyond the grave. (She had been married to his brother, who killed them when he caught them in bed together.)
Really, really creepy variation in Sammy Keyes and the Hollywood Mummy. Sammy's mother Lana, an actress, fakes an ID so she can claim to be 25. Unfortunately, her new birthdate is the day her boss's wife died. He thinks Lana is the reincarnation of his wife, and he tries to kill both of them so they can be reincarnated together.
Katherine and Thaddeus Valentine in Mortal Engines, Tom and Hester in A Darkling Plain.
Horlick and Claire Minton from Kurt Vonnegut's Cat's Cradle die in this way, falling to their deaths while still holding each other's hand. According to Bokononism, this is especially common with two people in an exclusive karas (aka True Love Soulmates); if they don't die together, one will quickly follow the other anyway.
Two examples in The Amber Spyglass: when people die, their daemon dissolves into its component particles, and the person's mind goes to the Underworld, a Nothing After Death. Lyra and Will find a way to let the mind out into the living world, where it also dissolves and allows the person to have the same fate. Also, Balthamos, having completed his mission, simply loses the will to hold himself together and disintegrates, rejoining him in a way with Baruch.
And Will and Lyra themselves, who couldn't be together in life, but will be able to reunite in the land of the dead.
In Dragonfly In Amber, Claire finds a pair of skeletons, almost like the page image, in a cave, and reflects on this trope.
The Story of Edgar Sawtelle has two: as Edgar lies dying, he is greeted by his dead dog Almondine. When he's finally good and dead, he is also reunited with his father, and finds himself able to speak for the first time ever.
In the Discworld novel Reaper Man, Ms. Renata Flitworth was engaged to a nice young man. Said man went across the mountain to make his fortune, but never returned. At the end of the book, in a Crowning Moment of Heartwarming, Death himself takes her spirit to an unnoticed spot deep in the mountains. Then, we see his spirit come out, at Death's request. So they get to be together as they fade away.
J. R. R. Tolkien's tragic lovers Beren and Lúthien from The Silmarillion. They are separated and reunited in death, twice! Special because, being a human and an elf, they would not have had the same fate after death (elves are bound to the world for as long as it lasts whereas humans are fated to leave it forever after a short while), but, through divine intervention, got the one exception. After their first death they were sent back for a short time to live a happy life together, and after their second death Lúthien's spirit was allowed to follow Beren's out of this world, as human souls do.
Tuor and Idril. Tuor was a mortal Man and Idril a Noldorin Elf. When Tuor grew old, they headed together toward West on their ship Ëarramë. It is claimed Tuor alone of all Men has been accounted to the Elder Kindred whom he loved.
Aegnor and Andreth are a variant. Andreth died and left the world forever. When Aegnor died, he could not follow her because being an elf, his life is tied to the world's. So he refused reincarnation and decided remaining on the Halls of Mandos forever because being permanently dead was the closest that he could get to be together in death with Andreth.
Likewise Arwen in The Lord of the Rings chose a mortal fate after death in order to be with Aragorn even if she survived him long enough to go to Lothlórien and die on Cerin Amroth where she made her promise in the first place. She also famously is Lúthien's descendant (so is Aragorn) and near-likeness.
Túrin and his sister Niniel in Narn i Hin Húrin.
In a less heartwarming example, Denethor ordered himself and Faramir burned in a pyre when he thought the latter had been killed in battle.
The end of the Last Herald-Mage Trilogy by Mercedes Lackey has Vanyel reunited with Stefan/Tylendel as ghosts. They're still around six hundred years later, too, to provide a handy assist to the modern heroes.
At the end of The Day Watch, after Alisa gives her testimony, Igor chooses to dematerialise along with her.
Wuthering Heights. When Edgar Linton is buried next to Catherine, Heathcliff takes the opportunity to open her coffin and look at her. He bribes the sexton to ensure that he'll be buried on her other side when he dies and knocks out that side of her coffin so they can be sealed in together. Then he wastes away and starves himself to death, whether with the specific intent of killing himself or just because all he cares about is dying so he can be with Catherine. After his death, various people claim to have seen his ghost with a woman.
Harry's own parents died within moments of one another, trying to protect their son from Voldemort.
Severus Snape's death allows him to reunite with his best friend and unrequited love, Lily Evans.
One of the few comforts Albus Dumbledore had while waiting for his impending death was the fact that he would be reunited with his family soon. Considering that the curse killing him was the result of him trying to use the Resurrection Stone to see them again, one can (morbidly) interpret this as the stone giving him what he wanted after all.
If Harry's speculation that Grindelwald truly had cared for Dumbledore (romantically or otherwise) is true, then he counts as well after his death at the hands of Voldemort.
The Deadly Distant Finale to Jon Cleary's The Golden Sabre mentions that the male and female leads died in a plane crash several decades after the main events — holding hands, happy to be together, even in this.
In a non-romantic example, the Distant Finale of Douglas Reeman's HMS Saracen reveals that the ship's captain died something like twenty years after the main story. A minor character realizes the probable cause of death was a heart attack brought on by seeing film of Saracen being used as a target for a missile test, and thinks, So even at the end, they were together.
In "Not From Detroit" by Joe R Lansdale, an old man beats up Death with a wrench when Death claims his wife. When Death explains that he can't let her come back to life, the old man asks Death to take him as well since he and his wife wanted to die together. Death agrees and brings back the wife just long enough so that they can die holding hands together. Death is even nice enough to let their souls out during the ride to the afterlife so they listen to tunes on his radio.
Sadly averted in the case of Drizz't and Catti-brie. Catti-brie's afterlife is a private one, and Drizz't will not be able to go to her side when he finally dies.
In Septimus Heap, one of the important characters is a ghost named Alther: Formerly a wizard, he now flies around the castle as a ghost. When he was alive, he loved another wizard named Alice Nettles, who also loved him. Alice Takes A Bullet for Princess Jenna, saving her life but killing Alice. However, Alther joins her new ghost, and sits with her every day for the six months it takes for her ghost to become fully mobile. And they go on to have a very happy death together.
In Aunt Dimity's Good Deed'', Dimity tells Lori that she and her fiancé Robert MacLaren celebrated their honeymoon in the afterlife. This and an unwillingness to meddle in Lori's life are the reasons she gives for her two-year absence.
The eponymous fern from Where the Red Fern Grows does not appear until the end of the book. When Big Dan is killed by a cougar, Little Ann loses the will to live and dies as well. They are buried next to each other and the symbolic fern grows near the dogs' graves.
In The Phantom of the Opera, Erik, who sleeps in a coffin, makes a reference to this trope. He notes to the object of his affections, Christine, that he will "have the coffin enlarged... for later on, when we come to the end of our love."
A Dog of Flanders ends this way. All their lives they had been together, and in their deaths they were not divided...
In Mistborn, Elend is killed in the final battle when he leads an army of men on a suicide mission. Vin attacks Ruin in a way that kills them both, stating that Elend was the only reason she had left to live. The new God Sazed later tells their friends that he has spoken to them, and they are happy where they are. He even arranges their bodies so they are holding hands as they lay among flowers.
In the Warrior Cats novel Crookedstar's Promise, Mapleshade mocks Crookedstar, telling him that he has lost everything because all his loved ones died. Crookedstar epically tells her off, informing her that now all his loved ones wait for him in StarClan, so when he dies, he'll be with them again.
In another novel, Bluestar's Prophecy, as Bluestar lies dying, her deceased mate Oakheart comes to lead her to StarClan, where she can not only be with him, but with her mother, sister, and kit as well.
Rather painfully subverted in Warriors: Omen of the Stars: The Last Hope. Spottedleaf made a promise that this would happen with Firestar when he eventually dies; however, shortly before this happens, Spottedleaf is killed Deader Than Dead and undergoes Cessation of Existence.
Rhaegar won, damn him. I killed him, Ned, I drove the spike right through that black armor into his black heart, and he died at my feet. They made up songs about it. Yet somehow he still won. He has Lyanna now, and I have her.
In The Jungle Book, when Mother and Father Wolf die Mowgli sings their death-song and seals them in their lair.
In Edgar Pangborn's short story "Tiger Boy", the title character and his friend (lover?) Bruno don't die in each other's arms, but they are taken back to Bruno's village for burial, the implication being that they'll be buried side by side.
In the Jeffrey Archer short story "Old Love", from A Quiver Full Of Arrows, when Phillipa, one of a married couple of Oxford doctors, dies of a heart attack, her husband William shoots himself despite no-one having had the nerve to tell him the dreadful news, apparently because he needs to see her and settle their last argument (over a crossword answer). They were serious rivals as undergraduates but admitted their love for each other when they were both contendors for an academic prize, and for the rest of their lives "Legend had it that they were never parted for more than a few hours". *sniffle*
In Percy Jackson and the Olympians, Beckendorf and Silena get this. When Silena dies, she says she won't be reincarnated, and instead goes to Elysium, so she and Beckendorf can be together.
In The Kane Chronicles, Julius and Ruby Kane get this. Julius becomes the host of Osiris, god of the dead, and rules over the underworld, with Ruby at his side.
Subverted in Number the Stars.Peter's last wish was that he be buried next to his dead fiancée Lise. Her family wanted to oblige, but he was killed by the Nazis and buried in an unmarked grave.
At the end of the novel of Double Indemnity, Phyllis and Walter commit suicide together by jumping off the stern of a ship.
In Things Fall Apart, an elder of the Igbo village dies after a long illness. His first wife, whom he had been married to for decades, hears the news and dies the same day.
"The Ghost of Garden Lounge" from Time After Time, a collection of short stories about time travel, features a jukebox that allows people's consciousness to travel back in time to a particular point in their lives based on a song that was important to them at the time. In the story, a guy named Pete goes back to save his girlfriend Mary from being shot by her ex-husband and ends up getting shot himself. Pete then goes back to save him and the process keeps repeating, until one day the ghost of Mary hitches along for the ride. This time, they both get killed, but it's a happy ending, because their ghosts are happy together in death.
Implied to case at the end of Sweet Piglet with the piglet and its master.
The Giverimplies that he plans to be Released so this will be the case with him and his daughter, Rosemary.
There are two variations in Academ's Fury, the second entry of the Codex Alera:
Doroga and Amara talk about the dangers they will face during their fight against the Vord. Doroga says that he would be sad to die, since he would leave behind his daughter Kitai, but he is consoled that he would get to reunite with Kitai's mother, who had died years earlier. Later, when things begin to look imminently grim, he laughs and jokes with Amara that it was a good thing they had earlier decided what there was to look forward to.
The Little Match Girl reunites with her late grandmother in the afterlife. While the girl is getting cold at the streets, she goes burning her matches and daydreaming, and she finally uses all the remaining matches and watches her grandma and it's the latter who carries the girl to heaven.
"The Bride Of Corinth": A young woman who was sent to a monastery against her will, died, and returned as an undead to sleep with a young man reveals that her lover will die, and asks from her mother that they will be burnt on a pyre together.
When Thistle the gnome is given the offer to become a paladin for his god in Spells, Swords, & Stealth, he reluctantly accepts but names a single condition: upon his death he goes to the same afterlife as his late wife rather than the afterlife paladins get.
In The Slave by Isaac Bashevis Singer, Jacob's wife Sarah dies in childbirth. Because she is not Jewish, the town elders have her buried outside the cemetery grounds. Jacob takes his newborn son and leaves for Jerusalem. 20 years later, Jacob returns to Pilitz and discovers that the town has grown and that the cemetery has grown so much that the place where Sarah is buried is now within the bounds of the cemetery. The place where Sarah was buried was not prominently marked and unknown to the Jews of Pilitz. Jacob is weak and dies during the visit to Pilitz. By coincidence (or perhaps, by a miracle), as a grave is being dug for Jacob, the bones of Sarah are found. The town decides to bury them together, side by side.