I'd recommend 'The Stars My Destination' by Alfred Bester. It has a rough and gritty feel as it follows a man's journey of revenge in a far - flung future with complex social and technological landscapes. Then there's 'Snow Crash' by Neal Stephenson. This novel dives into a world where the internet has taken over in a very seedy and gritty way, with a lot of chaos and power struggles.
One gritty sci fi novel is 'Hyperion' by Dan Simmons. It presents a complex and often dark universe, with different characters' stories that are filled with grit and struggle. Another good pick could be 'The Windup Girl' by Paolo Bacigalupi. It shows a post - apocalyptic future where genetic engineering has run amok and the world is a very tough and gritty place to survive.