I really can't comment on many American sports, but I do know one thing - soccer:
Real Madrid 1999ish-present. They win the La Liga title about every other year, oh and they have won the Champions League a couple of times: key players - Raul, Roberto Carlos, Figo.
Manchester United of the mid to late 90s. Completely obliterated the English league every year (bar 1998
), as well as winning the treble in 99 (English Premiership, FA Cup and the Champions League). Key players: Peter Schmeichel, Roy Keane, Paul Scholes.