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.
Stanislaw Lem’s The Cyberiad. It’s an anthology style and takes place in a far future where most of the characters are robots, focusing often on two constructors who compete with each other in achieving some goal first or building the best machine for a contest.
Other than the Tarkovsky’s production, it’s been adapted into movies rather badly, but Lem’s Solaris is a fine read as well.