There are several sports teams whose team names do not end in the letter "S," including the Major League Baseball teams called the Boston Red Sox and the Chicago White Sox. The National Basketball Association has several teams whose names do not end in "S," including the Utah Jazz, Orlando Magic, Miami Heat and Oklahoma City Thunder teams.
There are no National Football League teams that have team names that do not end in the letter "S," although some professional teams in the past did not have S-ending names. These include the Tonawanda Kardex and the Providence Steam Roller.
In the National Hockey League, there are also several team names that do not end in the letter "S." These include the Minnesota Wild, Colorado Avalanche, and Tampa Bay Lightning teams.
Team names may often end with "S" because the letter makes the word plural, which indicates a team. It would be awkward to say "Denver Bronco," or "Green Bay Packer." On the other hand, it would also be nonsensical to say "Minnesota Wilds" or "Boston Red Soxes." Many team names are rooted in rich history and have had several name changes. For example, in the NFL, the New York Jets were originally known as the New York Titans, and the Chicago Bears were originally called the Decatur Staleys.