I’m currently working on a book in which the main character’s parents died in a somewhat ghastly car accident. I haven’t decided yet if my MC was a part of the accident, which would make the death of her parents all the more traumatic. I am debating now if the "parent death by car accident" thing is too cliché. I do want her parents dead, as it is important to the plot. I feel like you hear about parents dying in a car accident a lot in TV shows, movies, and books, and I don’t want do do something that has been done way too many times to the point where my readers don’t sympathize with the MC as much as they should.
I just got up to this part of my own story, where I needed the protagonist's parents to have died years ago. My immediate thought was car accident... that was my red flag that it's used far too often.
Because my protag was from Algeria, it got me researching and I discovered there was a Civil War in Algeria (~150,000 deaths) right around the time was protag was a young child. It instantly provided a much richer background for my character and his parents, despite my initial hesitation about using it: Is it morally wrong to use tragic historical events as character background/development?
I don't like to use the word lucky for something so tragic, but I was lucky that the circumstances fell into place to give me a different scenario than 'car accident' so you may not have something like that depending on your context. But there's definitely more creative ways.
This might sound morbid, but in Google, click on News then search for "couple dies..." and you'll get a whole list of news items with different circumstances of how couples die together.
I shouldn't have to say, there are many ways two people can die together.
A terrorist bombs a theater they were attending, or opens fire with an automatic weapon and they were both directly in the line of fire. Or (real world) they were grocery shopping together and were attacked.
They could both have been vaccine deniers, and both died of Covid.
They could have been together when a bridge collapsed.
They could have been caught in a hurricane and drowned. Or on an aircraft headed out on vacation, that went down.
They could have died together in a earthquake, or in a tornado. In a house fire at night, due to faulty wiring.
Your job is imagination. If you think a car crash is cliche, imagine something else.
The reason why "car accident" is so popular is that it's plausible, both in itself and that it would kill both parents, it's commonplace so as to not draw undue attention, and it does not impose a direction on the story.
If you wish to replace it with something else that works the same, check for the most common causes of death in the appropriate age group, and pick one that would reasonably kill both.
You should note that many forms of death will work differently. For instance, the parents were killed when hit by a meteor. This is so freakish and unusual that your readers will expect it to mean something. Also that characters will have heard of it and connect the child to it -- possibly, if their name is unusual, for years after.
Likewise, if the parents were killed by deliberate poisoning, the question arises of who the murderer is, whether the child is in danger, and all the rest. If it's merely omitted from the story, the reader will miss something. (Of course, a car "accident" could also be murder, but a writer would have to write that in.)
Maybe they went to view the wreckage of the Titanic in the Titan submersible and it imploded.
Of course most people know only 5 people died in the Titan. But maybe by the time your story is published most people will have forgotten the details.
Or maybe the parents were adventure tourists and went on a group climbing Mount Everest and the whole group was wiped out in an avalanche or snow storm there.
Maybe their frozen corpses are now landmarks on one route to the summit, since it would be too dangerous to attempt to carry their corpses down the mountain — even injured but still living persons have been left because it would be too dangerous to try to carry them down. The protagonist may have copies of photos of his parent's corpses and may think about forming an expedition to recover their corpses, even though experts say it would be impossible.
Maybe both parents were working in the World Trade Center on 9-11-2001.
Several decades ago an apartment building was destroyed and several people were killed when a nearby natural gas pipeline exploded.
Seven-year-old Arthur Briggs was left at home in the care of his grandmother when his sea captain father, Benjamin Briggs, his mother Sarah, and his two-year-old sister Sophia Matilda sailed from New York with a cargo for Genoa, Italy in October 1872 in the ship commanded by Briggs. The Mary Celeste.
You may have heard about the famous Kelly family of Philadelphia. A family legend claims their ancestor emigrated to the USA on the last voyage to the USA made by the City of Boston before it disappeared in early 1870 on a voyage back to Britain.
And if your story isn't set in the 19th century, don't worry, maritime disasters still happen in the 21st century.
There have been four shipwrecks in the 21st century where over a thousand people died, and dozens more where more than a hundred died, and still more where tens of people died. Only 27 passengers and 5 crewmembers died out of over 4,000 people on the cruse ship Costa Concordia when it sank in 2012, and only two people wrre missing and presumed dead out of 1,153 passengers on the cruise ship MS Sea Diamond when it sank in 2007.
You should be able to find a maritime disaster which happened about the right time and place for your story on this list.
Wikipedia has a list of lists of 21st Century disasters.
There should be a number of disasters which happened about the right time and place for your story.