What I’ve read, more or less in order of preference:
1) Earth Abides (plague)
2) Alas, Babylon (nuclear war)
3) Lucifer’s Hammer (comet)
4) Scarlet Plague (er, plague); in the public domain & therefore free
5) The Stand (plague)
6) One Second After (EMP)
7) The Road (deservedly last) (who knows?)
The three most popular with Twitter:
1) The Dog Stars
2) On the Beach
3) Station Eleven
The full Twitter list, with original comments and virtually no editing.
Maddaddam trilogy (Margaret Atwood)
Walker Percy-great politically incorrect satire of post-apocalyptic US of A set in Louisiana.
Yarbro’s The Fourth Horeman (plague). Herbert’s The White Plague. One Second After. Hoyle’s The Last Gasp and Brunner’s The Sheep Look Up (environmental). Stirling’s Dies the Fire. Robinson’s The Wild Shore. Orgill’s The Sixth Winter.
A Boy And His Dog At The End Of The World is quite good and a good deal warmer than is typical of the genre. Also The Girl With All The Gifts/The Boy On The Bridge were great, horrific reads about a lethal fungus pandemic.
“Shiva Descending” is terrible but suitably depressing.
Harlan Ellison also published as No Blade of Grass. By the author of the Tripods trilogy, and of a lesser apocalyptic novel The Ragged Edge.
Shelley’s The Last Man, though it’s turgid. Adair’s Ebola K. Mayhar’s Monkey Station. Budrys’ Some Will Not Die. Hicks’ Season of the Harvest. There’s like a bajillion zombie-poc books, a few good; Ringo’s Black Tide Rising series is best.
David Palmer, Emergence; John varley, Slow Apocalypse; Riddley Walker by Russell Hoban
Day of the Triffids; Blindness, by Jose Saramago; The purple cloud, by M. P. Shiel; Black Feathers and The Book of the Crowman by Joseph D’Lacey
“made by hand series” by James Kunstler; Silo series by Hugh Howey
I think NK Jemisin’s broken Earth series fits. Start with Fifth Season.
The Andromeda Strain; The Postman; Lord of the World; The Unincorporated Man; Cloud Atlas
Greg Bear: Blood Music, The Forge of God
Anthologies: Man after Man: an Anthropology of the future; Defying Doomsday
A Canticle for Leibowitz is a fine book, although it takes place long after society collapses.
Arkady Strugatsky, Roadside Picnic
Dmitry Glukhovsky, Metro 2033
Ben H. Winters, The Last Policeman (first of a trilogy)
Does World War Z count?
Am I missing something? Please let me know and I’ll add it.