Final Fantasy
There are two main types of Final Fantasy game: the main series, where the games are just numbered with Roman numbers, and several related games and spinoffs. Each of the games in the main series have very little to do with each other, with its own setting, story, and characters. Some exceptions include Final Fantasy X and X-2, the sequel, or Final Fantasy XIII and Final Fantasy XIII-2 and Lightning Returns. But the games are connected through the gameplay, themes, and 'style'. Newer sequels and prequels are Final Fantasy X-2 and the Compilation of Final Fantasy VII games and films.