Existential Novels

Hey book, I enjoy reading existential novels. I think I've read the most famous ones already, so I'm hoping you can recommend me a few more that I may not have heard of.

Books I have read that most would probably call existential:

Camus – The Plague
Camus – The Stranger
Dostoevsky – Notes from the Underground
Kafka– The Metamorphosis
Kafka– The Trial
Sartre – Nausea

What should I read next? I eagerly await your responses.

You've read all the best ones, but I'll see what I've got

Hermann Hesse - The Glass Bead Game
Louis-Ferdinand Céline - Journey to the End of Night

And probably some other works by those authors too I guess.