Thanks for the tag @The_Penniless_Author 😀 💕
1) Generally post-apocalyptic, although I like both when done well.
2) There are lots - The Walking Dead springs to mind as one of the first comics I read (although I still need to go back and finish it). I'm gonna go Triffids though!
I still maintain that the best of this genre is to be found in videogame format - The Last of Us and Fallout, for example 🥰🙃