Their Bowl resume was quite good too...
Georgia beat B1G Something Ohio State in the Peach Bowl
Alabama beat Big Xii Champion Kansas State in the Sugar Bowl
Tennessee beat ACC Champion Clemson in the Orange Bowl
South Carolina beat ACC Champion Clemson in the Regular Season
Florida beat Pac-12 Champion Utah in the Regular Season
LSU beat B1G West Champion Purdue in the Citrus
Not every team contributed, but Alabama, Florida, South Carolina and Tennessee beat a P5 Champion, LSU beat a P5 Divisional Champion, and Georgia beat a solid B1G Something team in the Playoff. 6/14 SEC Teams had a meaningful OOC win in either the Regular Season or a Bowl Game. My guess is that the other four P5 conferences COMBINED cannot match that using the same criteria.
Go TCU! Beat the Dawgs! Then, the Frawgs will have 2 meaningful OOC wins this year over the B1G Champion and the SEC Champion to go along with the Cyclone Cy-Hawk win! (j/k). That game didn't mean much in the big scheme of things since Iowa didn't even win thier division, but ISU did have the biggest OOC win in the Big Xii in the Regular Season.