Deathworld (Harry Harrison) is a classic scifi trilogy from the '60s. It was kind of a "macho adventure fantasy", like James Bond in a scifi setting. Same author had a similar character style with his Stainless Steel Rat series.
The stories have twists and turns in the plot to keep it about as interesting as a James Bond plot. Which is to say, not that great, but entertaining enough now and pioneering-the-mainstream for the day.
Deathworld by Harry Harrison. I've been waiting for some screenplay writer to stumble across this one, and if I had to guess James Cameron probably did, but just didn't tell anyone.
SLAN by A. E. van Vogt.
The Witches of Karres by James H. Schmitz.
Lord Kalvan of Otherwhen, and Paratime by H. Beam Piper.
However the best of all, is maybe only slightly less know, since the author is certainly extremely well known: Tuf Voyaging by George R. R. Martin. An absolutely fantastic collection of stories about an ecological engineer.
I am not sure about top 3, but if I had to reread something I've read before, I'd start with Dostoevsky's 'Idiot', continue with "За миллиард лет до конца света" by Strugatsky brothers, and maybe I'll reread the Permutation City by Greg Egan.
As for the Three Body Problem, I find it unique in that it realisticly represents the humanity's place in the galaxy (a fly on the wind shield). Lui Cixin's cosmic sociology [0] rings true to me too. The idea of laws of physics being the result of the activity of advanced civilizations, while not original (see Lem's “The New Cosmogony”), is fascinating nonetheless. The story of how 'right' moral choices in the context of that world lead to the end of humanity is another original bit.
[0] https://whatever.scalzi.com/2014/11/11/the-big-idea-liu-cixi...
Whatever the solution, or at least, path forward, is, it is never 'more aggression', especially from a position of power.
I kind of expected that on my first sample set (Ishmael/Accelerando/A Gentleman in Moscow), but even the second one (Priory of the Orange Tree/Traci Lords:Beyond it all/Civilized Man's Eight Deadly Sins) is severely tilted to "everybody is reading it!"
A last try with a decided "60's Scifi" slant - Small, still voice of trumpets/The Tomorrow People/Deathworld. And I get Hitchhiker's Guide, War of the World's, Rainbows End.
I don't look for book recommendations to learn what everybody is reading, those books are inescapable anyways. I'm looking for thematically relevant, but might surprise and delight me.
Doing this well is hard even with curated lists and experts, but it's definitely possible to do better by just weighing popularity less heavily.
