End of the world/Post Apocalypse is one of my favourite genres.
"A Canticle for Leibowitz" is great. I think I should put it in the reread list. The follow up,
Saint Leibowitz and the Wild Horse Woman is worth the read but not as good.
The obvious book missing from your list is John Wyndham's
The Day of the Triffids. Or does a Triffid fall into the "zombie..." category?
The Chrysalids is another from him.
George Turner's
The Sea and Summer (that's the title on my copy) was one of the last paper books I reread. It is an interesting tale split between some people in the future looking back how the fall happened.
Hugh Howey's
Wool is the latest one I have read. Remnants of humanity living in an underground silo. An excellent read. The rest of the series is in my TBR list.