USC from 1980-2001 - a couple higher highs but more mediocrity as well
Notre Dame from 1994-2011
Georgia from 1984-1996 (not quite as long)
Texas from 1984-2000 is pretty close (but with a couple conference championships)
Washington from 2001-2015
LSU went from 1974 to 2000 without much more success
Maybe we define those rough patches differently. Texas and Georgia are pretty pertinent comparisons, and idk enough about Washington's history but have never thought of them very near the top class of programs, but USC/ND/LSU seem to be not nearly as apt. Admittedly, Nebraska has always been somewhat of a weird outlier as far as consistency.
USC finished #12, #13, #15, NR, #9 (Pac-10 and Rose Bowl champs), NR, NR, #17, #9, #9, #22, NR, NR, #25 (Pac-10 champ), #15, #11 (Pac-10 and Rose Bowl champ), NR, NR, NR, NR, NR, NR
Notre Dame finished NR, #13 (Orange Bowl appearance), #21, NR, #22, NR, #16 (Fiesta Bowl appearance), NR, #17, NR, NR, #11 (Fiesta Bowl appearance), #19 (Sugar Bowl appearance), NR, NR, NR, NR, NR (they're fairly close but they're also weird to compare because they have no conference affiliation .
LSU had a nice run starting in 1984 going #16 (SEC champs, Sugar Bowl appearance), #20, #11 (SEC champs, Sugar Bowl appearance), #5, #19 (SEC champs), and then they pretty much sucked during the 90's.