
"Chocky" by John Wyndham
"This is How You Lose the Time War" by Amal El-Mohtar and Max Gladstone (a new all-time fave for me)
"The Book of Strange new Things: A Novel" by Michel Faber
"The City and the City" by China Miéville
"The Fifth Science" by Exurb1a
"The Initial Fold" series by Nick Adams
"Peacemaker's Code" by Deepak Malhotra (still not sure why this is not more well-known)
"Eifelheim" by Michael Flynn (a most unusual premise and a gob of seemingly inane stuff to get through at about the 2/3 point, but IMHO worth it)
"Providence" by Max Barry (heart pounding)
"Hench" by Natalie Zina Walschots
"Orange World" by Karen Russell (short stories but many qualify as sci-fi, very memorable to me)
And here are some definitely well-known examples that also stick in my head:
"Infernum" by Jayson Adams
"The Fourth Wing" and "Iron Flame" by Rebecca Yarros (more fantasy than sci-fi, but very well done if you can handle two or three extended and explicit sex scenes)
"Rabbits" by Terry Miles (book includes some hidden hints and puzzles that lead you to things outside the book
"We are Legion (We are Bob)" series by Dennis Taylor
This is How You Lose the Time War - Amal El-Mohtar and Max Gladstone (actually now one of my all-time favorites, without regard to genre. Just amazing)
Children of Time - Adrian Tchaikovsky
The Book of Strange New Things - Michael Faber
Ted Chiang's short story collections (Exhalations and Stories of your life and others)
Daemon - Daniel Suarez
The City and the City - China Miéville
Roadside Picnic - Arkady and Boris Strugatsky (this one still haunts my dreams at times)
We Are Legion (We Are Bob) (Bobiverse Book 1) - Dennis Taylor (just finished this series for book club)
Galatea 2.2, The Overstory, Bewilderment, The Gold Bug Variations - 4 different books, all by Richard Powers - what can I say, the man is a genius and a treasure
Eifelheim - Michael Flynn - ok, this book can be a slog at times, but it is very rewarding for those who persevere, and has stuck in my brain for many years
Chocky - John Wyndham - A quiet, delightful surprise
Providence - Max Barry - This book flows like a movie. It will make a great movie. I found myself LITERALLY out of breath a couple of times
Hench: A Novel - Natalie Zina Walschots - Quirky, memorable
The Peacemaker's Code - Deepak Malhotra - Why hasn't this guy written more sci-fi?
Orange World and Other Stories - Karen Russell - OK, maybe not strictly sci-fi, but this book tickles my brain
GUILTY PLEASURE SCI-FI FAVORITE: The Vaz series by Laurence Dahners. I think I've read that series 3 times now.
"This is How You Lose the Time War" by Amal El-Mohtar and Max Gladstone. Without a doubt one of the most amazing and beautifully-written books I've ever read (and I read a lot). Astonishing.
"Children of Time" by Adrian Tchaikovsky. If I had read the book jacket short-description of this book in a book store, I probably would have put it back on the shelf, but I am so glad I didn't do that. Seriously.
"The City and the City" by China Miéville. A difficult beginning. To be honest I had to start this book two or three times before it finally clicked, but when it did... oh man.
"The Book of Strange New Things" by Michel Faber. This is a story that has been done by a couple of other authors (notably Mary Doria Russell in "The Sparrow"). But this book is so delicate, so lovely that I have purchased and given copies to my nerdy-wordy friends more than any other. It sticks in my head and I still think about it in some way almost every week.
"Bewilderment" and "The Overstory" by Richard Powers. OK, to be frank, anything by Richard Powers is worthy of your attention. There are very few authors working today who can construct prose like this man. Perhaps his work is not for everyone, but if your brain works a certain way, you will no doubt fall in love with this guy's writing. He has many books, but for those with a sci-fi slant, also check "Galatea 2.2" and "The Gold Bug Variations"
"Exhalation" and also "Stories of Your Life" by Ted Chiang. Two collections of memorable short stories, including the story that the movie "Arrival" was based on.
"Providence" by Max Barry. Wow. This needs to be made into a movie NOW. This book was so intense at points that I had to stand up and put it down because my heart was racing. A very fun, quick read.
Some sci-fi gems that were scattered in between those listed above include: "Starplex" by Robert J. Sawyer, "The Clockwork Dynasty" by Daniel H. Wilson, "Solar Warden" by Ian Douglas, "Hench" by Natalie Zina Walschots, "The Peacemaker's Code" by Deepak Malhotra, "Hail Mary" by Andy Weir (don't let the naysayers fool you, this is a fun book with a lot of interesting ideas), and the entire "Vaz" series by Laurence Dahners.