im not sure of all them but i know that the Miami Dolphins have gone undefeated, and the New England Patriots have gone undefeated.
No NFL teams went undefeated in 2009.
Pittsburg, Baltimore and Cleveland
5
The Dallas Cowboys, along with the rest of the NFL teams, went on strike in the 1987 NFL season. In addition, the Cowboys (and the other NFL teams) went on strike during the 1983 season. There were no "replacement" games in 1983 unlike 1987.
Colts & Saints
No nfl teams are playing today
32 NFL football teams
Click on the 'The NFL in 1950' link on this page to see the teams and rosters of the teams that were in the NFL in 1950.
In the NFL their are 32 teams
17-0 Miami Dolphins 18-0 Patriots
Detroit Lions went 0-16 in 2008
No NFL teams have no cheerleaders. They all have them and many of them.