I knew I was listening to a lot of audiobooks when I started having strong opinions about favoured and disfavoured narrators. NYT recently profiled Eduoardo Ballerini as a kind of "voice of God", but, for me, that's John Man. What Don LaFontaine is to movie trailers, John Man is for audiobooks, at least to me.
If you want a place to start, I can recommend the recordings by Mark Nelson - https://librivox.org/reader/251
He recorded a lot of pulp classics - "The Cosmic Computer", "First Lensman", "Hour of the Dragon", "Princess of Mars", "Space Viking". Professional quality recording, great voice, charming books.