I will only include the one's that made me stick through thick and thin. Mostly no romance, if it's harem then you should expect that the MC is just using them for greater benefits. I don't like DUmb characters so you should also expect that most of the Male leads here or Female leads are smart or sharp. half of my list also include survival and teaches you some bitter reality lesson unlike those cliche novels that makes you scared or dream about nonsense fantasy stuffs.

I JUST RANDOMLY PLACE THE NOVELS AND I WON'T RANK IT. ( for me, they're all the best on their own way and techniques) 

[disclaimer: as I said, ‘mostly’ no romance- what I meant is in the survival stories, and if the protagonist is a man. But if the protagonist is a girl, they’ll be really romance. Book like that (top tier books with Female Mc w/ no romance) are very rare. I myself having some troubles finding them.]