"The book club, the high school teacher or college professor, the parent, the extremely bossy friend... someone pushed these books on you, and you were unexpectedly pleased." (Goodreads)
While making this challenge, I noticed that the books for which I had to create a new icon had high Goodreads rating scores (above 4). So, extrapolating, those books on this list you may have never heard of MAY be 'undiscovered' gems worth seeking out. Update: Or maybe I am just naive, as evidenced by Marta Gabnai's observations in the Comments tab.