There are 2 possible outcomes if you're getting hit by a car, got isekai'd or getting yourself a wife
Or have the vehicle show up in homeroom, apparently being a new transfer-student. But it is a delinquent that hates you. And then see it show sympathy for an abandoned baby-stroller, and have your heart go kyun. Then you proceed to seduce it.
Or wake up in the hospital and [insert gimmick here].
Or have your musician boyfriend become depressed, until he encounters another girl with the exact same name (since the story was named after the female love interest) who plays music and rekindles his love for music (and women?).
Or have your girlfriend travel through the multiverse, until she manages to save an iteration of you. Then you have an affair on your gf with your AU gf.
Or you might be bamse - the world's strongest bear. In which case the blood runs, and the intestines disappears, and bamse never runs again. (this one differs from the rest as it is not a manga I have read. Instead it is a popular children's song 🎶 from when I was a kid.)