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.
Tanith Lee. “The Silver Metal Lover.” “Don’t Bite The Sun.” “Venus Preserved.”
She’s mostly known for fantasy, but her science fiction is great.
Joanna Russ. First openly gay SF writer. “Picnic On Paradise” and “The Female Man.”
R. A. Lafferty. Insanely good short stories.