Love pieces like this. They are catnip for heavy readers in this genre. Here are things I have read that come to mind as influencing me.

Classics

The Last Man (1826) - Mary Shelly

EARTH ABIDES (1949) - George R Stewart

I Am Legend (1954) - Richard Matheson

Brain Wave (1954) - Poul Anderson

NO BLADE OF GRASS (1956) - John Christopher

On the Beach (1957) - Nevil Shute

Level Seven (1959) - Mordecai Roshwald

Alas Babylon (1959) - Pat Frank

A Canticle for Leibowitz (1960) - Walter Miller

The Drowned World (1962) - JG Ballard

Cat's Cradle (1963) - Kurt Vonnegut

Hero's and Villains (1969) - Angela Carter

Malevil (1972) - Robert Merle

The Sheep Look Up (1972) - John Brunner

The Forever War (1974) - Joe Haldeman

Dahlgren (1975) - Samuel R. Delany

Survivors (1976) - Terry Nation (his novelization of the series, very different, very insightful)

If you only read one, read Earth Abides.

Modern Takes

The Stand (1978) - Stephen King

Riddley Walker (1980) - Russell Hoban

The Gunslinger (1982) - Stephen King

Warday (1984) - Whitley Strieber and James Kunetka

The Postman (1985) - David Brin

Always Coming Home (1985) - Le Guin

Galapagos (1985) - Kurt Vonnegut

Natures End (1986) - Whitley Strieber and James Kunetka

Post 2000

World Made by Hand (2008) - James Howard Kunstler

One Second After (2009) - William R. Forstchen

The Girl With All the Gifts (2014) - MR Carey

Hope this is helpful.