Individual games that cost your team a National Title

Would love to see a full list. I think this captures most of the ones for the SEC in terms of National Title Games and/or bowl games that were played that definitively decided the National Title:

4- Alabama
2021 lost to Georgia
2018 lost to Clemson
2016 lost to Clemson
1971 lost to Nebraska

4- Oklahoma
2008 lost to Florida
2004 lost to USC
2003 lost to LSU
1987 lost to Miami

2- Georgia
2017 lost to Alabama
1982 lost to Penn St

1- Auburn
2013 lost to Florida State

1- LSU
2011 lost to Alabama

1- Texas
2009 lost to Alabama

1- Florida
1995 lost to Nebraska

I believe there are also dozens more back from the old days before there were official national title games.

For Auburn:

1983- lost to Texas in the regular season. Game did not affect our bowl slot. We would have played Michigan in the Sugar Bowl either way. But had Auburn not lost to Texas in Week 2, we would have undoubtedly been 1983 National Champs (should have been anyway)

1958- We were defending National Champs and attained #1 again in 1958 before a 7-7 tie to Georgia Tech tumbled us back down to #5. Had Auburn finished unbeaten/untied a second year in a row, we very likely would hold claim to the 1958 title instead of LSU.