Bob's little sister Alice was killed in what he would later call his greatest failure. He continues to fight for her, trying to 'fix' the world so that no one else ever has to go through this, or seeking to take vengeance upon her killers. Though doing so may make him a Well-Intentioned Extremist or outright evil, it's all worth it to him.
In order for him to never forget the reason he fights, he keeps a memento, often something that belonged to Alice, though it may just be something that reminds him of her. Sometimes, the 'something' may be her Soul Jar, and Bob is attempting to find a way to resurrect her.
Villains love to get their hands on such an item, if only to crush it in front of the their victim's eyes.
See also Orphan's Plot Trinket, Take Up My Sword, Death Notification, It Was a Gift, and Memento MacGuffin. When Bob is feeling particularly sad over Alice, he may hold the keepsake in a Cradle of Loneliness. If the Keepsake is a body-part of an entity being remembered, then it is this trope being combined with Creepy Souvenir.
Since this qualifies as a Death Trope, beware of spoilers.
- Bruce kept the letter Flashpoint!Thomas Wayne wrote to him. Thomas used his last seconds asking Barry to give it to him... and then Eobard shreds it, because he's a dick.
- In the tragic story "Starfall, Starrise" one of the human boys whose actions lead to the untimely deaths of Shale, Eyes High and his own brother keeps the hair ornament worn by Eyes High as a mark of his shame. Many years later he is found by Shale and Eyes High's son Skywise, who was born shortly before his mother's death, who forcibly retrieves the ornament but spares the human's life.
- Cutter keeps his late father Bearclaw's wolf-head necklace but doesn't have time to take it with him when humans set fire to the Holt. Returning to the spot some years later he finds its melted remains.
- X-23's locket, which contains pictures of her slain mother (whom Laura was forced to kill in a trigger scent-fueled rage) and her cousin, Megan. The locket was a parting gift from Megan when Laura was forced to send her into hiding to protect her from Kimura, and is the only thing she has left of her mother and family. She most prominently wore it in New X-Men, though it's only sporadically appeared since, often Depending on the Artist.
- Red Sonja's Chainmail Bikini is revealed in Queen Sonja to be a gift from her long-dead lover Kain. Its actually a Beautiful Slave Girl disguise used to infiltrate a sacrifice chamber and rescue their child allies. Kain was killed in action and Sonja wore the metal bikini as the last gift he gave her.
- In Up, Carl Frederickson's house and practically everything in it are a keepsake of his departed wife Ellie and the childhood promise he made to her.
- Starship Troopers: Invasion gives us Trig and her custom sniper rifle, a gift from her parents. Not long after she received the rifle, her family and everyone she knew was killed when the Bugs destroyed her home town.
- Word of God states that in The Book of Life, Manolo's first guitar was a gift from his mother, who died when he was a baby.
- The titular character in Anastasia has one without even realizing it for half the movie; the necklace she wears was given to her by her grandmother, and doubles as the key for the music box Anya also received from her. The necklace is the only physical evidence of her old life and birthright she has, and she can't even remember who gave it to her.
- Cinderella: Cinderella has her late mother's ball gown, which she alters to make it a bit more fashionable to wear to the royal ball, still keeping the pink and white color palate. Unfortunately, Lady Tremaine encourages her daughters to tear the gown to shreds by pointing out their beads and sash were used on it, which the girls had thrown away earlier.
- Pocahontas: Early in the movie, Pocahontas is given her late mother's necklace, in both memorial and as a symbol of her betrothal to Kokoum.
- The Princess and the Frog: Tiana is shown to have kept the medal her late father earned in WWI, and the fine-dining advertisement flyer that he used to show her his dreams for his restaurant. Eudora also brings Tiana her father's gumbo pot as a present to commemorate her buying the property for her restaurant, since she is working to fulfill what was originally his dream.
- Moana: Moana wears the locket her grandmother gave her before she died. It also serves a functional purpose, since both Moana and her grandmother used it to store the Heart of Te Fiti.
- Scion signature character Horace Farrow carries a .45 revolver with him. His uncle Seth used it to kill Horace's (step)father and shoot out Horace's eye, but dropped it when Horace nailed him in the groin with a shotgun. It's heavily implied Horace carries it so that one day he can put a bullet from it through Seth's head.
- Every magic item in Geist: The Sin-Eaters has a tragic story to it; it just depends on whose it is. The scale goes from someone else's (Charms) to your own death (Vanitas) to the death of the ghost bound to it (Fetter) to the destruction of a geist (Deathmask) to the death of somebody famous (Memorabilia).
- Ajani Goldmane in Magic: The Gathering bolted his dead brother's axe head to the unused end of his own axe, and starts wearing Elspeth's cloak after her death.
- In Wicked, Glinda keeps Elphaba's hat and her green bottle when she believes Elphaba is dead.
- In Matilda, the Acrobat gave her shiny white scarf to her husband, the Escapologist, before her fatal circus accident. Later, after rescuing his daughter from being locked in the cellar by her wicked aunt, he left the scarf with the former before leaving to confront the latter and disappearing. When Miss Honey invites Matilda to her shack of a house for tea, she shows Matilda an identical white scarf, whence we find out that the Escapologist was Miss Honey's father, Magnus, and the wicked aunt was Miss Trunchbull.
- In Volume 4, Jaune has his armor, sword and shield reforged to use the gold metal of Pyrrha's shield and circlet. The most notable is seen with the shape of her circlet on the bottom of his shield. As well, he wears a sash around his waist similar to how Pyrrha wore hers.
- Ren modeled the blades of his weapons after a knife his father gave to him. The Volume 4 finale reveals he also kept the knife itself, which he uses to slay the monster that killed his parents and destroyed his hometown.
- When Neopolitan appears in Volume 6, she's wearing Roman Torchwick's Nice Hat.
- In Red vs. Blue, Carolina kept York's lighter, the only thing she has left of him.
- In Gunnerkrigg Court, James Eglamore keeps a knife that was a present from his old flame, the recently-deceased Surma.
- Homestuck: In the End of Act 5, after the Exiles are massacred, Serenity, WV's firefly companion, hangs around PM.
- Crankrats: The photo of young Jack and Maddy. Subverted via Dramatic Irony however.
- In Girl Genius Gil fell in love with Agatha shortly meeting her, and proposed not long after (framing it as a way of keeping her safe from his father). Almost right afterwards an emergency occured, ending in her faking her death. Gil then wore the ring he made her around his neck. Subverted in that he continued to wear it after he found out she was still alive, as they have yet to graduate to Official Couple.
- The origin of the Crystal Heart in The Shadow Shard as well as Spike's egg. They're both remnants of his mother.
- In The Legend of Korra, Mako wears a red scarf, which is a common fashion statement for Firebenders in Republic City. But he is unusually attached to his scarf. When he goes to the restaurant with Asami Sato, he wears it with his tuxedo. Later on, she buys him a silk scarf, which he does not wear, so she asks why. Mako tells Asami the scarf is all he has left of his murdered father. Later, Mako gives the scarf to his paternal grandmother.
- Katara from Avatar: The Last Airbender wears her deceased mother's necklace.
- In Adventure Time, Marceline has Hambo, a teddy bear which is all she has to remember her Parental Substitute by after his Artifact of Doom drove him crazy and senile, making him forget her. It was stolen from her and sold by her Bastard Boyfriend hundreds of years ago, only to be regained several seasons later and be completely destroyed mere episodes after that.
- King of the Hill: Hank Hill replaces the ball-top shifter of his new pickup truck with the shifter of his old pickup after the old one is destroyed by a train.
- In the Gravity Falls episode "Carpet Diem", after a secret bedroom was discovered in the Mystery Shack, an upset Grunkle Stan quietly takes a pair of glasses similar to his own out of the room. Later, while Dipper, Mabel, and Mabel's friends mess around with the carpet in the secret room, Stan has a melancholic moment with the glasses. Of course, Gravity Falls being what it is, the actual meaning behind both the glasses and Stan's attitude over the discovery of the secret room wasn't made apparent until late in the series, when a certain Walking Spoiler (I.E. Grunkle Ford) was officially introduced.
- In Guardians of the Galaxy (2015), it is said that Drax the Destroyer sleeps with a doll named Mr. Rhinopuss, who used to belong to his daughter before she was murdered by Ronan the Accuser.
- In the Crystal Gems from Steven Universe, it is revealed Blue Diamond has been keeping Pink Diamond's "human zoo" functioning and is housing all of her Quartz soldiers there as a memorial to the fallen diamond. Yellow Diamond derides Blue Diamond's habit of collecting anything related to Pink Diamond as useless clinging to the past.
- In Over the Garden Wall, the lantern the Woodsman carries contains his daughter's soul, which he keeps lit with oil from the Edelwood trees. Unfortunately, the Beast lied about whose soul was in there; it was actually the Beast's soul, and he'd been tricking the Woodsman into keeping it lit with tree oil from trees that used to be children that got lost in the woods and died from despair/exhaustion. The Woodsman is less than pleased when he finds all this out.
- In Star Wars Rebels, Hera has her Kalikori, a small, traditional Twi'lek totem that honors past family members, including her deceased mother and younger brother. Following the death of her beloved Kanan, she adds him to to the Kalikori.
- In Castlevania (2017) Dracula keeps wearing his wedding band after his human's wife's brutal murder by the church. At the end of season 2 when he is staked, decapitated, and his remains burned, the band is the only thing left unscathed.
- The key that Rapper/Actress/Singer Dana Owens, a.k.a. Queen Latifah, often wears around her neck belongs to the motorcycle her brother was riding when he died.
- Several religions keep a whole collection and record of these things. The most famous ones are the Catholic relics - the most poignant and tragic (and sometimes, creepy) are those that belonged to martyrs, but any inspirational beloved will do. Relics come in three flavors: body parts of the actual saint (can vary from drops of blood in a bottle or tiny pieces of bone to an entire body, bonus points if it's uncorrupted), items that were worn in a regular basis by the saint (i.e.: Saint Pio of Pietrelcina's gloves which he used to cover his stigmata), and items that were merely touched or blessed by that saint (such as a robe, a piece of the Holy Cross, a favorite shepherd's crook, etc.) Several miracles are credited to relics, no matter what flavor they are: i.e., in Italy the vial that contains the blood of Saint Gennaro is said to have its contents miraculously liquified during the saint's feast. During the medieval ages there was a black market of relics, where diverse Catholic groups would steal them and either sell or smuggle them to other places. An example would be Saint Catherine of Sienna's head.
- Skydivers habitually wear the parachute closing pin as necklace. Should a skydiver die in an accident, often a friend of the deceased skydiver will begin to wear the necklace of the deceased one as their memorial.
- Penn Jillette has his right ring-finger nail painted red in memory of his dead mother. He also wears his father's ring but, as he always snarks when telling this story, none ever asks him about that.
- Richard E. Grant wears two wristwatches. One was given to him by his dying father, and is permanently set to time in Swaziland, the land of his birth.