From 1987-1998, every team that won the finals went back to back. The reverse parity era.
When the Lakers won the finals in 1987, every team then on that won the finals went back to back to win the championship twice (or in the bulls case 3 times) in a row
Lakers - 1987
Lakers - 1988
Pistons - 1989
Pistons - 1990
Bulls - 1991
Bulls - 1992
Bulls - 1993
Rockets - 1994
Rockets - 1995
Bulls - 1996
Bulls - 1997
Bulls - 1998
In a 12 year span, 4 separate teams won the finals. It’s the longest span in the history where every team that won a finals went back to back.