The Montreal Canadiens have made the playoffs the most times.
New York Yankees
Los Angeles Lakers
Every team has made the playoffs in at least once year. The Columbus Blue Jackets made the 2008-09 season playoffs, making it their first time to qualify for the playoffs. Before that, they were the only team not to make the playoffs.
The Boston Bruins
The Boston Bruins are one of the original six teams in the National Hockey League. In the team's 90 year history they have made the playoffs seventy times not including the season that did not have playoffs because of a lockout.
The Houston Texans 2012 answer: all NFL teams made it to the playoffs.
I am no expert, but im sure every NFL team has made it to the playoffs, the houston texans have recently made it to the playoffs, so it cant be them.
As of the 2008 season, the Mariners have made the playoffs 4 times. They won the AL West Division title in 1995, 1997, and 2001 and were the Wild Card team in 2000.
The Cowboys have been in the playoffs 29 times since they became an NFL team in 1960.