Infinite Jest is far too high and there are numerous omissions but that is certainly a list of 100 books that are mostly very good.

His tragedies are far above his comedies IMO.

King Lear, Macbeth, Titus Andronicus, Julius Caesar, and Othello are all masterpieces, each could take the rest of your life in rereads and study.

Six Feet Under still stands far above every other example of the form.

Context helps. The author was a hardline conservative and it was written in the aftermath of WW2. A whole lot of Lord of the Flies is explained by the sort of person who serves in WW2 against the Nazis but considers themselves “of that sort of nature”, votes Tory, and attended a public school.

Lord of the Flies took all the same tired old boring mess of Hume and “The man in nature” and melded it with the abusive legacy of English schoolboys.

I write for a living so yes, I’d call it essential. You can’t write well without reading well

The Death of Ivan Ilyich first.

Then if you have a background in 19th century history, War and Peace. The problem with W&P vs Anna Karenina is that W&P is not really a conventional story. It’s as much, or more, a polemic aimed at the duality of Russian society embodied in the twin battles of Austerlitz and Borodino. Austerlitz is a battle fought for vain glory and frivolities and Borodino is fought for a higher and more noble goal, to save Russia. Without that background knowledge it gets very confusing very quickly and the last 1/8 or so lacks impact.

AK is a much more conventional novel and probably an easier read.

“Buddenbrooks” by Thomas Mann
“Play It as it Lays” by Joan Didion
“East of Eden” by Steinbeck