good candidates all, but you have to give the Lifetime Achievemant award in this category to the Raiders.
Sure, if you're 10 years old. Otherwise, we're talking about a franchise with a 53.5% lifetime winning percentage, five superbowl appearances, three league championships, and a fistful of Hall of Famers (Otto, Shell, Brown, Madden, Upshaw, Biletnikoff, Long, Hendricks, Allen, pretty soon Guy, eventually Davis, and I'm sure I'm still missing some), in addition to many more HoF finalists (Brown, Wisniewski, Hayes, etc.)
Compare that to the Arizona Cardinals and their 41.9% lifetime winning percentage, who have been in existence since 1920 and have made the playoffs 8 times. Not a typo. Eight. Although, in fairness,
they did win a league championship back in 1925 when it was awarded to the team with the best overall record (i.e. no postseason). They went 11-2-1 that year, with wins over the Milwaukee Badgers, Columbus Tigers, Kansas City Cowboys, Duluth Kelleys, Buffalo Bisons, Dayton City Triangles, Rock Island Independents, and Hammond Pros. It was probably the high point in franchise history.