As of 2022-03-22
I’m very close to this one. The MLB Ballpark app (as long as you log all of your games) will tell you how many stadiums you’ve been to and which teams you’ve seen play a game (regardless of location/stadium.) Right now (3/22/22) I’ve not yet seen the Orioles, Yankees, Blue Jays, or Phillies live. But with trips planned to see the Cubs play in all of those cities this year (and Phillies at Cubs @ Wrigley this year as well), this item will be done by the end of the year!