Gonna toss you something completely different here. It's not a standalone novel, but rather an entire self-contained universe which is coming up on its 40th birthday with over two dozen complete books... and one last series in progress.
Fortunately, all but the final series are available for you (or anyone else) to peruse online in full for free, at whatever pace and in whichever order you choose.
<span class="bold">Elfquest</span>. (Direct link to the "Read" page, where all the free stories can be found.)
I've been a fan of the World of Two Moons since discovering the original black-and-white issues at my local comic book shop in the early 80s. The first fully colorized print collections hit my local bookstore a few years later; they still have a treasured spot in my library.
Another out-there pick: the original four-book storyline for
Teenage Mutant Ninja Turtles. They are nothing, I repeat NOTHING, like the vast majority of the dumbed-down cartoon and movie adaptations, though the current animated remake running on Nickelodeon comes a lot closer. Expect actual violence and danger, zero cowabungas, and strict adherence to the samurai code of Bushido.