Some of the standout games I remember spending significant time on: Load Runner, Karateka, Prince of Persia, Choplifter, Moon Patrol, Ancient Art of War, Autoduel, Castle Wolfenstein, Silent Service, Spy Hunter, Stellar 7, Summer Games, Winter Games, Wasteland, and the Ultima series.
Karateka and Choplifter actually sold me on the Apple II after playing them in BASIC class... and Choplifter inspired inspired the arcade game. A lot of quality and timeless titles here for sure.