For me, I suppose it would be Mallory’s The Death of Arthur. I audiobook-ed an abridged version and was surprised by just how much dramatic power it had near the end.

Also, even though I’ve lapsed as a believer, there’s a lot in The Bible that’s good on artistic grounds separate from religious significance. “I am with you always, even unto the end of the world.” or Psalm 23, for instance.

There is an aphorist, Francois Rouchefoucauld, whose book of maxims (free online) is almost gold from beginning to end.