Is there such a thing as a "clip fed" shotgun?

Ok everybody I just recently watched Terminator 2 for the nth time this past week. It many post-apocolyptic films, games, books, etc. the charecter is trying to kill baddies and runs out of ammo. Suck
So I ask you, in real life, do clip fed shotguns exsist? If so can a civilian purchase one? I heard that there is probably a law against them considering how devestating a shotgun is already.
Further more if I can get one I’d like to know where so that when I finally get around to stockpiling weapons and food for the end of the world, e.g. zombie uprising, I’d know where to get one.