According to the AV metric from Pro Football Reference, these 10 Bills players are the best to ever don the red, white, and blue.
The analytics movement in football is still in its infancy, but there are plenty of statisticians out there trying to come up with the next big number that brainy front office execs can use while building their rosters.
Pro Football Reference has an interesting stat called approximate value (AV for short). You can find a (very detailed) explanation of the metric here, but essentially, it's a football version of Bill James' 'win shares' statistic.