Clockwork Orange by Anthony Burgess
Brave New World by Aldous Huxley
The Stranger by Albert Camus
The Most Dangerous Game by Richard Connell
Animal Farm by George Orwell
The Chosen by Chaim Potok
Catcher in the Rye by J.D Salinger
Flowers for Algernon by Daniel Keyes
Tale of Two Cities by Charles Dickens
Not all of them are necessarily Highschool required reading, but they are mostly books I read around that time, and most are considered classics.