In 2002, the NFL added a 32nd team to the league. When the Houston Texans joined, the league realigned and the Miami Dolphins almost became a member of the AFC South. It would have made sense but what would history have looked like if they had?
When the league expanded, the Indianapolis Colts moved from the East to the South and then controlled the division for years. The Dolphins were supposed to move to the South however, it would have made sense.
Indianapolis is not in the South but they also are not in the East either.