A somewhat-recent example of a great novel that was recently discovered was "Stoner" by John Williams, which is about an English professor named William Stoner who stoically lived a seemingly unremarkable life that still evokes sympathy and empathy.

The book was first published in 1965, but failed to gain popularity. It took until 2013 to gain wide popularity, and is a contender as one of the greatest American novels.

Coverage about the book's resurgence was published in The New Yorker (paywalled at https://www.newyorker.com/books/page-turner/the-greatest-ame...) and The Guardian (no paywall, via https://www.theguardian.com/books/2013/dec/13/stoner-john-wi...).