It is a common practice to keep something that belongs to a dead relative/friend/lover/etc as a means to remember them.
For that reason, that something is commonly a valuable, long-lasting item; a pendant or a photo are particularly popular choices, as are weapons
But sometimes, a character instead keeps something related to their dead beloved one that should've been more... disposable. Or otherwise a petty item that the character is being sentimental about.
It can be a food item that their loved one had prepared before their untimely death. It could be their last message on their phone or e-mail. It could be a worn-out item that the dead usually uses/wears such as clothing, dining utensils etc. It could also be an unwrapped present, provided that they keep it unwrapped.
It is often a sign for the character that does this to be someone who holds their dead loved one very dearly. Either that, or someone who has Excessive Grief
Anime and Manga
- In Mobile Suit Gundam SEED Destiny, Shinn Asuka keeps his sister's cellphone for many years after her death, mainly for the recording of her voice in the voicemail greeting.
- In Guardians of the Galaxy, Starlord has kept a present from his deceased mother unopened for 26 years.
- In 21 Grams, the protagonist keeps an answering machine message of his deceased husband saying he's about to come home.
- In The Reconstruction, a grieving widow has a heated argument with her teenage daughter because she washed her deceased father's clothes, the last place on Earth with his scent.
- Inverted in Pan's Labyrinth. Captain Vidal keeps his late father's broken pocket-watch on him at all times as a memento. His father had smashed it against a rock in his dying moments so his son would "know when a real man died." Captain Vidal spends the movie constantly tinkering with it and keeping it in perfect working order. Interesting in that this inversion is shown as something evil people do.
- An episode of True Blood featured the main characters puzzling over whether they should eat, keep or simply throw out a cake made by a recently deceased, still in the fridge.
- A humorous inversion in an episode of Married... with Children. Al takes a trip to buy Aunt Maddie's famous potato pie, only to find out she has died. Her funeral turns into a competition, between all the mourners, to get the last piece of pie... by stealing it before it's buried with her.
- On House, Wilson struggles to wash a coffee mug that still has leftover lipstick from Amber. There's not going to be a print of those lips, in the universe, ever again.
- Monk keeps the last birthday present his late wife gave to him... unopened.
- Bones. Brennan keeps unopened presents from a Christmas in which her brother played Santa and she thought her parents had returned.
- On Criminal Minds a comic book artist suffered a psychotic break after his girlfriend was killed by a street gang. He is shown regularly calling her old voice mail number just so he could hear her voice on the recording.
- Played for Drama on Breaking Bad. After another character's death, Jesse Pinkman is frequently seen calling her phone to hear her voice on the voicemail greeting. Eventually the phone is deactivated, and he calls it only to hear an automated intercept message saying that the number is invalid.
- xkcd - Admin Mourning. When a user dies their screen sessions remain, and you can't stand to reboot and wipe them out ("The Ghost in zshell").
- Averted in Adventure Time: Finn and Jake consider keeping the last pickle in the jar that Prismo made before his vanishment, but decide in the end that he would have wanted them to eat it. Then it turns out that dreaming after eating the pickles is key to letting Prismo return.
- Dave Barry had an article on Graceland where he interviewed some Elvis fans. One of them had kept a radio he'd given her, including the original long-dead battery and the wrapping paper.