Dick is pretty unique. Even looking over the "new wave" SF writers (from the 60s) he stands out and is on an extreme edge.
My picks would be Samuel Delaney for novels, especially The Fall of the Towers trilogy and Dahlgren.
Harlan Ellison is also awesome but mostly wrote short stories and novellas rather than novels.
He's a very interesting guy. He was was once called the most ornery man alive, and he is abrasive and argumentative and quick tempered, ready to sue if he feels his work has been stolen or mistreated. He forced James Cameron to add a credit for him to Terminator, which Ellison claimed ripped off his script for a short story adapted by Outer Limits. He also wrote the Star Trek episode City on the Edge of Forever, which won a Writers Guild award and a Hugo. He marched at Selma in '65 and edited the most seminal science fiction series of short stories that "blew up" the genre - Dangerous Visions
. he was a Yippie leader, and there's a series of videos of him speaking in the 60s.
Lots of his work has become films or TV shows, but he's such a weirdo (who I dearly love) that he often uses the pseudonym Cordwainer Bird if he thinks the film version screwed up his writer's vision. His short novel A Boy and His Dog
is terrific, and the movie was I think Don Johnson's first major role.
You might like this... https://www.youtube.com/watch?v=RZvcKB9vQO0
There's a ton of videos of his appearances on talk shows, and radio interviews. He's a very fast talking, articulate, interesting speaker.
John Brunner, Kurt Vonnegut, Alfred Best come to mind as somewhat similar...
There are quite a few writers who you can tell tried to "do" a PKD style novel, sometimes with great success, sometimes not - but almost never as a career.