The Browns rank a very deserving #3. Crucial to that is their 8 titles, but there's some great history here too. The NFL was founded in Ohio in the 20s, and then the AAFC came about in the 40s with the Cleveland Browns as their flagship. When the two leagues merged, the Browns won the next NFL title, proving naysayers wrong and discrediting the notion that their AAFC titles weren't meaningful.
There's also the quirk of the owner of the Browns in the '90s deciding to move the team, and the community rising up and getting the deal arranged that the "Browns" would stay in Cleveland even if the owner moved his organization elsewhere. No team means more to their city than the Browns do to Cleveland, not even the Packers.
The Cowboys' success is really quite stunning. They're often called "America's Team", and are consistently rated as the most valuable franchise in the NFL. This shouldn't have happen. The Cowboys are in Dallas, not New York or L.A. Teams from Dallas in other sports are basically irrelevant, yet this 60s era expansion team has caught hold of the nation's attention above teams from larger markets with longer histories. The 5 Super Bowl titles, and 8 total appearances are a big part of it, but the mystique goes deeper than that.
The only AFL team on this list. Owners of arguably the most iconic uniform and image in the league. RaiderNation is legendary. The team has had great success despite its relative youth, though they've fallen on hard times recently as owner Al Davis' eccentricities have become less likely to be labeled "genius" and more likely to be labeled "insane".
The Colts have a pretty crazy history. They can be said to be descended from teams of the following names: Dayton Triangles, Brooklyn Dodgers, Brooklyn Tigers, Boston Yanks, New York Yanks (not not the Yankees), and Dallas Texans. They then became the Baltimore Colts and established themselves as a strong team under legendary quarterback Johnny Unitas. In recent years they've continued as a very well run team which certainly hopes to add to their title count before the end of Peyton Manning's career.
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