I tend to divide apocalypse (and occasionally dystopia) books into mechanism (how the world ends) or focus (survival versus ‘something else’).
I divide apocalypse into:
–Fantastical–end of the tech civilization brings about magical creatures, or a way of life dependent upon unknown physics. Ilona Andrews’ Kate Daniel’s series, The Trees, The Twelve (Trilogy), Bone Dance
–Alien–end of civilization due to invasion of aliens (currently rare). Dawn by Butler (arguably; I can’t recall what leads to end of humanity), Extinction Point
–Nuclear–older, enjoying a resurgence: A Canticle for Leibowitz, Brace for Impact (Southern Grit trilogy), Alas, Babylon, The Last, Emergence, Swan Song, Who Fears Death, Wool
–Asteroids—The Last Policeman, Lucifer’s Hammer, On the Edge of Gone, The Calculating Stars
–Environmental disaster–New York 2140 by KSR, Blood Red Road, Trail of Lightning, The Water Knife, California, Depth, Bannerless (Bannerless series), The Sheep Look Up, Wool
–Electromagnetic Pulse (EMP)–a growing field. Most are self published so far. After the EMP by Harley Tate begins a series, as did L.A. Dark. Ashes is a YA EMP that was published by a national house. Dies the Fire (Emberverse, Stirling) and is the largest-published series
–Disease/Genetic– Station Eleven, The Stand, The Day of the Triffids, Sleepless, The Dog Stars; The Death of Grass; Orleans (also environmental); The City, Not Long After; Blindness
–Unknown Cause–Emergence, Dissension, California, Take the Long Way Home, Wool
–Zombies are usually a metaphor for disease outbreak. Most zombie stories are about how to recognize a threat and then how to survive, and eventually, re-form community
—Disease/zombies—The Girl With All the Gifts, Falling Sky, World War Z, Feed (Newsflesh Trilogy), Zone One, Positive
–Survival–London: Apocalypse, Devoured, Rot and Ruin, The Walking Dead, The First Days (Rhiannon Frater series), The Death Doll, Ex-Heroes, Rise Again, The Enemy (kind of Lord of the Flies thing)
–The Reapers are the Angels is Faulknerized zombies
-Courtney Summer’s This is Not a Test is high schoolers facing zombies. Heartbreaking.