If you are looking for both the post apoc setting and top quality writing.

One second after

Works made by hand series

Alas Babylon

On the beach

The stand

World war z

Lucifers hammer

Looking for long series to get lost in

Going home

is my favorite series currently at 11 books

Black autumn first few are really good

299 days a good read

The rest of the one second after series good but not classic like the original

I’ve read tons more but these are the ones I would say wouldn’t disappoint most Preppers