There are some great novel recommendations here, but I wouldn’t say that most of them are lesser-known.
What are your recommendations?
As for me, I’ve exclusively read well-known novels, except if you consider someone like Alfred Bester obscure, for example.
One exception: Misha Burnett’s Endless Summer: Twelve Strange Tales of Mankind’s Future. It’s a collection of exceptionnaly well-crafted stories. It ain’t a novel, though.
Cordwainer Smith’s Instrumentality universe. Smith was an interesting person himself, he was in national intelligence.
The Instrumentality was a very strange and vivid world building paradigm, and his writing is very compelling. Too bad there isn’t a hundred more stories.