If we're talking college sports - and I don't know if we are - then I will throw out the 2001 Miami Hurricanes.
For one season, the 1982-83 Sixers were phenomenal. The 1966-67 76ers have been called one of the greatest teams ever assembled.
That Oilers team was phenomenal, the one year they lost to the Calgary Flames, the defenseman put it past Fuhr to give the Flames the winning goal otherwise they would have won what 6 in a row?
From 1962 on, Manky's Yankees have eight World Series titles. The St. Louis Cardinals have five in the same time span.
To add a random group... Syracuse Lax with a Gait brothers in the late 1980s. They lost one match in three years and won three championships.
The early 70s A's won five straight division titles, and three World Series. However, their regular seasons weren't great..especially in the three World Series years: 93, 94 and 90 wins. They actually won 101 in 1971 and 98 in 1975 and then got swept in the playoffs both times.