Conversation so far:
when did the philadelphia eagles enter the nfl
The Philadelphia Eagles were established in 1933 as a replacement for the bankrupt Frankford Yellow Jackets.
Who won the 1933 NFL Championship?
The season ended when the Chicago Bears defeated the New York Giants in the first ever NFL Championship Game.
How many championships do the Chicago Bears have?
The Bears have won nine NFL Championships, including one Super Bowl.
Is nine championships the most by an NFL team?
The Green Bay Packers have won 13 league championships, the most in NFL history.

Question: What teams haven't won?
Self-contained rewrite: What NFL teams haven't won a championship?