Outside of Larry Kehres (DIII), these are ALL of the DI coaches with a win percentage of .800 or greater (as of 2021) and have coached 10 seasons or more. There are 14 names. Of those, 4 coached all or a portion of their games before the modern era of football (1932). Of course Ryan Day hasn’t coached 10 seasons yet, but where do you think he would rank on this list? Would you guess 2nd overall and 1st amoung DI coaches?
.929 Larry Kehres† - Mount Union (1986–2012)
.881 Knute Rockne† - Notre Dame (1918–1930)
.864 Frank Leahy† - Boston College (1939–1940), Notre Dame (1941–1943, 1946–1953)
.855 Doyt Perry† - Bowling Green (1955–1964)
.853 Urban Meyer - Bowling Green (2001–2002), Utah (2003–2004), Florida (2005–2010), Ohio State (2012–2018)
.837 Barry Switzer† - Oklahoma (1973–1988) - .836 - Nebraska (1973–1997)
.833 Fielding H. Yost† - Ohio Wesleyan (1897), Nebraska (1898), Kansas (1899), Stanford (1900), San Jose State (1900), Michigan (1901–1923, 1925–1926)
.829 Robert Neyland† - Tennessee (1926–1934, 1936–1940, 1946–1952)
.826 Bud Wilkinson† - Oklahoma (1947–1963)
.812 Jock Sutherland† - Lafayette (1919–1923), Pittsburgh (1924–1938)
.806 Dabo Swinney - Clemson (2008–present)
.806 Bob Devaney† - Wyoming (1957–1961), Nebraska (1962–1972)
.806 Clarence Munn† - Albright (1935–1936), Syracuse (1946), Michigan State (1947–1953)
.804 Sid Gillman† - Miami (OH) (1944–1947), Cincinnati (1949–1954)
.800 Nick Saban - Toledo (1990), Michigan State (1995–1999), LSU (2000–2004), Alabama (2007–present)
† = College Football Hall of Fame
.894 Ryan Day - Ohio State (2019–present … not counting 3-0 as interim HC in 2018)