The 2003 anime has a parent and child example in the movie with Wrath walking into Izumi's arms at the Gate. It's also implied that this is the true reason why Lust wanted to be a human: so she could be with her former lover in death.
Hansel and Gretel from Black Lagoon, as shown in the ending of episode 15 — the only one not to feature the standard Revy ending. Gretel's soul is seen walking barefoot on a beach, and at the end her and Hansel's spirits are standing side by side, watching the sea and holding hands..
Katsuya and Kyoko Honda. Katsuya dies of illness several years before Kyouko is fatally struck down by a car... and when she dies, the last thing she sees is Katsuya's soul, welcoming her into the afterlife.
Rather ironically, the driver that hit Kyouko with his car... did it because he had a heart attack at the steering wheel. And he dies too. For worse, he's the father of Komaki Nakao, one of Tohru's schoolmates.
Subverted in Weiß Kreuz: when Tot is fatally stabbed, Nagi has a telekinetic meltdown which destroys the house they're in and apparently kills him. Seeing the two lying next to one another in the wreckage, Yoji moves Nagi's hand to rest on top of Tot's in a Together in Death pose. After the surviving cast members have left, however, Tot gets up... and in another episode or two, Nagi shows up in perfect health and the incident is never mentioned again.
Not to mention the girls in the lighthouse. Even the one who precipitated the whole awful series of events is there.
In Fushigi YuugiSuzuno "Byakko no Miko" Osugi and her Seishi, Tatara, had to wait for decades to get together, as Tatara's soul was bonded to the Shinzaho's resting place and Suzuno died of old age in the Real World. The anime adds a scene in which their souls are reunited on Earth and then depart together to the afterlife in front of Miaka's brother, his best friend, a local taxi driver and Suzuno's grandson.
In Mazinger Z, Dr. Hell found the bodies of a man and his lover who had been Buried Alive together for being caught trying to break their Star-Crossed Lovers destinies. One half of each body was destroyed, so he stitched them together to create his most loyal supporter — Baron Ashura.
In Shin Mazinger, the two halves of Baron Ashura are actually Tristan and Isolde.
Jack tries to do this during his duel with D-Carly by playing a trap card that would cause both of their life points to drop to 0 at the same time. (It was a Shadow Duel, meaning the loser would perish; he was willing to die with her at this point.) She manages to stop him by activating a trap card that causes only her life points to 0 before Jack can activate his. Jack wasn't too happy about this turn of events.
This is later played straight with the Godwin brothers, Rex and Rudger, who, after Rex is defeated by the team of Yuusei, Jack, and Crow, walk together into the afterlife.
Ai no Kusabiends like this for Iason and Riki. For better/worse, they didn't have to die together. Only Iason was fatally injured after having his legs cut off, but Riki willingly stays by his side to have One Last Smoke and die with him.
After Oboro commits suicide both to not kill Gennosuke and to screw up Ofuku's plan, Gennosuke kills himself as well.
Subverted earlier, when a maddened and dyingKagerou tries to kill a severely wounded Gennosuke too to invoke the trope, but Oboro's Anti-Magic powers kick in and manages to stop her. Kagerou dies leaning on him instead.
Given a very dark and tragic twist in King of Thorn with the final meeting between Kasumi and Shizuku. One of the two has a chance at living, but wants them both to die together so they can be Together in Death. The second wants the first to take the opportunity to go on living. They argue over it. Tragedy, Freak Out, and The End of the World as We Know It ensue.
In the movie version of Eureka Seven, Eureka claims that she will continue to exist as long as her lover lives or did not forget his memories. This implies Eureka won't ever outlive Renton and will automatically follow Renton in death, regardless of her will when that time comes.
Chinkyuu and Ryoufu in the Ikki Tousen manga. The first even lampshades it in her Famous Last Words, which come right before she crushes her Magatama and pretty much commits suicide.
Sakura Gari has Souma invoke this when he and Masataka are trapped by Sakurako in a burning warehouse, and he loses hope to survive. In a twist, Masataka manages to save them both.
Shishio and Yumi plot to take over Hell. They didn't exactly die together (Yumi died in the middle of Shishio's fight with Kenshin, stabbed by Shishio himself as she knew and wanted him to, and Shishio himself went the Karmic Death way few minutes later, but are reunited in Hell itself. And soon they're joined by Houji, who had been imprisoned and later committed suicide.
In the (thankfully non-canon) OVA, Reflections the lethally ill Kenshin and Kaoru end up dying together under the cherry trees.
Claude, Hannah, and the Macken brothers (Luka and Alois/Jim) in Black Butler.
Subverted in the end of the Cardcaptor Sakura manga, as Fujitaka does not need to die to see Nadeshiko again, since being one of the two reincarnations of Clow Reed (the other being Eriol) gives him the power to see her spirit.
Zabuza is fatally injured after pulling an epic Taking You with Me on Gato. He requests that Kakashi bring him to his Battle Butler, Haku - who earlier performed Taking the Bullet for him - and dies with Haku by his side, openly expressing a desire to go to the same afterlife as his one precious person. Kakashi tells Naruto, Sasuke and Sakura that he openly believes this wish was indeed granted. And confirmed to be the case much later, when Kabuto yanks them out of the afterlife as Edo Tensei zombies. Both they and Kakashi and highly offended by this desecration.
Subverted parent/child example with Kakashi and Sakumo. Kakashi dies during the battle with Pain, and he encounters his father, Sakumo aka the White Fang, at the precipice of the afterlife. They have a long conversation, but rather than proceeding to the afterlife, Kakashi is summoned back to the world of the living by Pain reviving everyone. Sakumo is okay with it, however, and says that he'll finally be able to reunite with Kakashi's long-dead Missing Mom.
Obito and Rin. When Obito/Tobi finally dies, the soul of his Lost Lenore Rin comes for him. His own soul then returns momentarily to the world of the living in order to prevent Kakashi's death, explicitly so that he doesn't get in the way of their alone time in the afterlife.
Deconstructed in CLANNADUshio dies in Tomoya's arms and then he dies soon after from despair.
Macross Frontier - The Wings of Goodbye invokes a variation with (Warning: Love Triangle Ending Spoilers) Alto and Sheryl. At the end Alto is Missing In Action, and Sheryl is in a coma, but they were each wearing one of the two Fold Quartz earrings that convey feelings and ignore the laws of time and space. Later Jossed by Word of God, who claimed utter confusion that people were interpreting the ending this way, and declared that Alto did find his way back to the Frontier colony and Sheryl did wake up from her coma, subverting the trope.
Gold Roger and his lover and mother of his child, Portgas D. Rouge, were reunited this way.
A non-romantic example could be Whitebeard and Ace after being separated for quite some time and were properly "reunited" after their deaths by being buried next to each other. Even more so, Ace is the child of the aforementioned Rouge and Roger.
In the Dressrosa arc, should Luffy die in the battle against Doflamingo, Law is fully willing to invoke another non-romantic example and follow him and Corazon in death, as penance for dragging Luffy into what he considers his fight. It's at this point that Law recognizes that Luffy is not just his ally, but his friend.
Alma and Kanda in D.Gray-Man. Also Bak's parents where after their deaths by Alma's hands, For arranges their bodies so that they were leaning towards each other and holding hands.
Grave of the Fireflies provides a brother/sister example. Two children starve to death in WWII Japan, but their much-happier spirits/ghosts are shown together throughout the film.
Alan's goal is to reunite with his true love in the afterlife. The opening shows his soul bird flying to the place hers went off to.
Alas this is probably a good example of a Macekre in which there is no such bittersweet ending. The original ending was a subversion; Izu (Alan) is given the chance to rejoin Marin/Marlin (Marie) and doesn't have the guts to go through with it, pulling himself back from the edge of the cliff Marin's spirit lead him to at the very last second. This leaves him, the broken betrayer, the only survivor at the end of the film.
In Ranma ½, this trope is conversed, but not actually carried out, after Ranma and Akane eat Love Mushrooms in the anime.
Ranma: Let go of my hand, babe! Akane: I can't, honey! Ranma: If you don't, both of us will fall. Now, take this bag and get Ryōga to help you back up the cliff! Akane: No way. I can't do that to you! We're getting married to each other, aren't we? A married couple should always be together, even when they die. If we can't be together in this life, then at least we'll be together in heaven.
Renda de Baroma and Duker Iq aka the local Battle Couple, in Victory Gundam. Not only that, but Odelo, Usso and Marbet have visions of Renda and Dukeractually riding together in a Harley towards the afterlife.
Cruelly used in Gundam 00. Lichtendahl Tschery dies in a Heroic Sacrifice to protect the girl he likes, Christina Sierra. Bad thing, it fails: after Lichty perishes, we find out that Christina has been fatally injured by shrapnel anyway. Then what's left of the Ptolemaios explodes, and their lifeless bodies are destroyed alongside it.
Invoked in one case, where Ryoichi Takahashi tries to kill himself with a knife after confessing to the murder of Chikako Ikeda in order to join Atsuko, the girl he was in love with (who committed suicide because Chikako stole Atsuko's best script and passed it as hers to make a movie out of it), but he is stopped by Conan with a Shut Up, Hannibal! speech.
In the Non-Serial MovieThe Time Bombed Skyscraper, Conan-as-Shinichi has been helping Ran to dismantle a bomb that is about to explode, kill them, and bring down the titular skyscraper. However, the bomb itself has been rigged specially to confuse anyone trying to defuse it, and Conan cannot find out how to go past that. (For worse, Ran's trapped in a small room with the bomb, and Conan-as-Shinichi is stuck at the other side of the door). As both of them realise that they're about to die, Conan-as-Shinichi gently tells Ran to do as she wishes because there's nothing else they can do, and they will at least die together◊. Then it's subverted, as Ran's decision ultimately saves them and everyone in there.
At the end of Part I of JoJo's Bizarre Adventure, Erina wants this for her and the mortally wounded Jonathan. Jonathan defies this trope, telling Erina she has to live not only for herself, but for a nearby baby girl whose mother had just diedwhile protecting the child. Erina honors Jonathan's last wish and escapes the sinking ship with the baby girl. Part II reveals that Erina never remarried and the baby, her adoptive daughter Elizabeth "Lisa Lisa" Straizo, grows up to marry her and Jonathan's son George and becomes the mother of Joseph Joestar, the hero of Part II.
At the end of Gatchaman II, the villain Gel Sadra has sustained a fatal injury from her boss X and makes her way to a cliff, where she gazes upon the beauty of the world and regrets trying to destroy it. Having lost her mother as a consequence of being The Dragon to X, she expresses the wish to be reborn and help the world. However, she hears a voice telling her that Gatchaman can handle protecting the world. With recognizing it as the voice of her mother, Gel Sadra dies, her body shrinking back to her true childhood age. Her spirit then rises from her body and walks off into the sunlight, at her mother's side.
In Hunter × Hunter at the end of the Chimera Ant arc, the Chimera Ant King Meruem is fatally poisoned by Netero's Rose bomb. He spends his final moments playing games with Komugi, the one opponent he could never defeat and the girl whom he grew to love. Komugi stays with him even after he warns her that the poison will kill her too. They die holding hands together.
While the original '70s Neo Human Casshern had a relatively upbeat ending, the '90s OVA remake Casshan: Robot Hunter has Tetsuya/Casshern die after sacrificing himself to defeat Braiking Boss. However, his spirit then rises from his body to meet his deceased parents, and the three become a beam of light that helps shut down all the enemy robots.
Also, from the same series, Mello is killed very shortly after his best friend Matt. There are also strong implications that it was their intention to sacrifice themselves from the start in order to orchestrate Light's death.
Mavis and Zeref finally die together when their mutual love activates the Curse of Contradiction
At the very end of The Vision of Escaflowne, when Hitomi is getting ready to return home, the souls of several dead people dear to the cast are watching over. They appear in this order: Van and Folken's parents Gaoh and Varie, King-Duke Freid and Princess Marlene, Folken himself and the Cat Girl twins Nadia and Eria, and Van's Parental Substitute Vargas.
The HentaiDorei Ichiba (English: Slave Market) ends with the main protagonist visualizing himself with his three sex slaves that died in the course of the three episodes, while laying mortally wounded in a battlefield.
Defied in Superior Cross. Umberto abandoned his wife when she was pregnant due to a deal he made with the townspeople to protect their unborn child fromHalf-Breed Discrimination. Decades later, he meets his granddaughter, Angelica, and learns that his wife had died several years ago. At the end of the chapter, he's talking to a painting of his wife and mentions that he'll be with her soon, but finds that he actually wants to keep on living (with her spirit then showing up and telling him that she's fine waiting for him). He's still alive and well four years later at Angelica's wedding.
Lyrical Nanoha: According to the tribute manga for the second movie, Precia was reunited with her daughter Alicia in heaven. Rather perplexing since, at the time of her death, she wasn't the sortof person you'd expect to go to heaven.
Variable Geo: Evil scientist and Torture Technician, Siritahi, loses the will to live during the climax of the final episode. She's last seen cradling Damian's lifeless body as the Jahana research facility burns down around them, until the ceiling gives way and collapses directly on top of them.
In the 1977 animated short The Rose Flower and Joe (Bara no Hana to Joe), Joe the Dogdevelops a romantic crush on a pink rose (who is partially sentient). The short ends with a now blind and weak Joe reuniting with the pink rose near the end of autumn. As he and the rose are dying, they share a final conversation with each other before reuniting together in the afterlife where they share a romantic kiss. The short is based on a children's story by Takashi Yanase with Sanrio working on the animated short.