Since the turn of the century in the league in the NHL, only two teams have made the postseason in the first round of the playoffs with a goal differential of -20 or worse: the Montreal Canadiens (2024-25 season) and the Washington Capitals (2023-24). A couple of years ago, the Capitals made the playoffs as the worst team in the modern era of the league in the NHL, including a -37 goal differential in the East.
Expansion West Division Los Angeles Kings team from 1969 playoffs named one of the worst postseason teams in the history of the NHL
The Habs also made the postseason this past season in the 2024-25 campaign in the East with a -20 goal differential in the playoffs.