In addition to the Cowboys and the Packers, the last team in the top three in all-time winning percentage is the Baltimore Ravens, with a winning percentage of .571.
That figure comes with a footnote -- The Ravens came into existence in 1996 when Art Modell moved his Cleveland Browns franchise to Baltimore. As part of a settlement agreement with the NFL, the Browns' history, records, stats, colors, logo, etc. remained in Cleveland and were inherited by the new Cleveland Browns, who began play in 1999. The Ravens are considered an expansion franchise as of 1996.
The full list of NFL winning percentages is here -- https://www.pro-football-reference.com/teams/index.htm Click on the column marked W-L%
That figure comes with a footnote -- The Ravens came into existence in 1996 when Art Modell moved his Cleveland Browns franchise to Baltimore. As part of a settlement agreement with the NFL, the Browns' history, records, stats, colors, logo, etc. remained in Cleveland and were inherited by the new Cleveland Browns, who began play in 1999. The Ravens are considered an expansion franchise as of 1996.
The full list of NFL winning percentages is here -- https://www.pro-football-reference.com/teams/index.htm Click on the column marked W-L%