Should your car ever wind up submerged in water a hammer could come in handy. Make sure it's a "break glass" type hammer, which has a point. Thick tempered glass is surprisingly strong.
Only the tesla truck claims to be bullet proof. This happened in a model y and the 5th person in the car narrowly survived because a bystander smashed the window.
The spring-loaded kind are a lot easier to use in a cramped car and by people with less upper body strength. However, those won't work on newer cars with dual-pane or laminated glass