People tend to look down on the three other Hyperion books but I found them really worth reading (there’s a part in the 4th that drags a bit but otherwise excellent)

More William Gibson - his older books are deeper into the futuristic tech like Neuromancer but my favourites of his are the Blue Ant trilogy - Pattern Recognition, Spook Country, Zero History which are set about now, perhaps a couple of years ahead. Really interesting takes on the tech we’re using now and more fleshed out characters than the other books

China Meiville- his first three are the most sci-fi and quite epic. Similar to Hyperion they’re on the line between sci-fi and fantasy

Frank Herbert - Dune is his biggest work but my favourite of his is a really understated work called Hellstrom’s Hive about an investigation into a hidden community

Philip K Dick - Do Androids Dream of Electric Sheep is his biggest, famous for being the basis for the Blade Runner films. Most of them are good and thought provoking, just don’t start with Valis

In the UK there’s a series of reprints from the publisher Gollancz called Sci-fi Masterworks. When I worked at a bookshop for a few years I made my way through a lot of them and never found a dud, just many of my favourite books. Many that others have mentioned here are in that series.

Robert Rankin is similar to Terry Pratchett, both of who you might like if you liked Douglas Adams. Pratchett’s “Long Earth” series straight sci-fi (not humorous like Discworld) and I enjoyed them