The Complete History of the NFL visualized
FiveThirtyEight.com, a subsidiary website of ESPN known for political and sports-related statistics and visualization, released a scoring schema ranking all the teams ever to play in the National Football League based upon the Elo Ratings system developed for ranking the world’s top chess players. This ranking system marries short-term and long-term success to calculate a score to determine how good a team throughout a season and over the team’s history.
There are other contrasting systems that aim to determine a ranking seen in college football (like the now-defunct Bowl Championship Series rankings which sought to aggregate several different polling systems into one system) and NFL teams (like ESPN’s brand-new Football Power Index which factors in team rest periods, travel distance, weather, and altitude in conjunction with on-field performances calculated by whether the starting quarterback is available and by other granular statistics like expected points per play.)
To see how your favorite team ranks historically (including defunct teams like the Frankford Yellow Jackets!) are available at this link.