Thanks for a legit comment. Lol. Definitely get one, as a knife will take way longer to cut and probably won't pop the window. Here's the link to the one I bought.
resqme The Original Emergency... https://www.amazon.com/dp/B01G6C18EC?ref=ppx_pop_mob_ap_share
It might depend on what they already have but...
Multi-Tool (Many will recommend a leatherman instead)
Glass Breaker (other brands/styles too)
There is also stuff like tools, ammo cans, mylar bags, oxygen absorbers, and some firearm accessories.