1.
Holy Bible
Finnegan's Wake
Infinite Jest

These are undisputed.

2.
Ulysses by James Joyce
Gravity's Rainbow by Thomas Pynchon

These are old-core and should be considered as equal for posterity's sake.
There are actually a great deal many volumes which 4chan.org/lit has come to a sort of consensus about.

The making of a new-core is not designed to replace the old-core, but to expand the knowledge as written down and accumulated over the course of so many years' discourses.

I suppose the britannica Great Books be used as a model; Harold Bloom's Western Canon should be accepted not as comprehensive but as part of the conversation as well. There are two versions of it also https://en.wikipedia.org/wiki/Great_Books_of_the_Western_World