I want to say BYU was the last team to leave a conference and think they would be better off Independent, then they turned around and rejoined one 10 years later. I don't know if they thought they could be the Mormon version of Notre Dame or what, but it was short lived. Always thought that was a weird move for them during the previous conference realignment talks. I guess UConn technically left the American to rejoin the Big East, also becoming an Independent in football, but that seemed to have more to do with a disagreement over TV revenue or something.