A quick sort by year of inception on Baseball Reference shows the Pittsburgh Pirates being tied for the second oldest franchise in all of Major League Baseball, trailing only the Cubs and Braves, both of whom are tied for first.
Because of the sheer age of the Pirates, they’ve played plenty of baseball games. Assuredly, they’ve also played a lot of games against certain teams. Any teams that were originally created with them are bound to be high on the list of games played, as well as divisional rivals once that format began to take shape.