That's a wide remit! You've probably read anything I might recommend!!
As far as modern authors go, I'm a fan of Margaret Atwood's novels - do you like her? How about some Kurt Vonnegut? You can't go wrong with him.
For the classics, have you read any Wilkie Collins?
For something a bit less well-known, "The Migrant Painter of Birds" by Lidia Jorge is a beautifully written novel that would have flown under my radar except that a writer gave it to me for my birthday having been recommended to do so by her writers' group - so if a bunch of writers recommend a book, I guess you can take it for granted that it's worth the read.
None of these are fantasy or romance.
It's so difficult to recommend books to other people, isn't it? Tastes differ etc. But I avoid fantasy and romance too.
Should I take it that you like adventure themes? Have you read Treasure Island then? There's a bookclub thread here and that's the next book up.