It really is hard to go undefeated, there’s a fair list of coaches in the modern era who have done it once. That list includes Saban, Dabo, Carroll, Stoops, 3 different Bowdens, JJ, Switzer, and a bunch of others others. Urban has done it twice and that’s pretty rare company in recent memory. Royal 2x, Osborne 3x, Paterno 5x, Bryant 3x Hayes 2x., Wilkinson 3x, Only counting perfect seasons btw. Petersen did it 2x at Boise so small asterisk
Saban is considered arguably the goat, but I think that title should be reserved for Gil Dobie. He had 14 undefeated and 11 perfect seasons. That included an 9 year tenure at Washington where he went 58-0-3. That’s pretty incredible for any period, hell its the same timeframe aggy claims most of theirs
The most perfect seasons by P5 teams are Michigan(15), Dome(13), OU(11), Bama(10), UT, USC, Corn (9)... all the rest.
Side note: aggy has 3, tied with Toledo, Eastern Michigan, Western Michigan and a bunch of others but behind powerhouses Colorado School of the Mines and Case Western Reserve, yet they still think they belong in the blue blood conversation. We think we are falling out of the club because of a horrible decade, they think they belong because of 3 good seasons in the past 2 centuries.