9. Quake 3
Quake 3 is a legendary game that did a lot for online gameplay and really furthered the genre while laying down the framework that many titles still benefit from today. For those who barely lived through the 90s and aren't dreadfully scared of 30 / accepting the results of time, Quake 3 was hugely important for online gameplay, as well as curved walls.
The sprawling maps of Quake 3 were revolutionary because unlike most games from this period they did not look like they had been created by a series of rulers and cubes. Rather Quake 3 had curves that added complexities to shooting and all of a sudden players would have to be more tactical.
Alongside fantastic multiplayer for players to enjoy with friends, this game was a huge leap forward in terms of online matchmaking and games like Call of Duty still benefit from the legacy of this game.
While it may not be as good to play now, Quake 3 illustrates that great games take strides to give players something new can result in legendary status. It's just unfortunate that 1999 was really the peak for this franchise.