It used to be Notre Dame, but it's no fun hating somebody that isn't very good.
Florida St, well, we beat them.
Ohio St? Maybe, some of their online base has gotten insane since Urban came aboard (no reflection on B1G here). Their inconvenient arguments last fall didn't set well with me ("But you played Mercer while we played OU" is a terrible argument).
Oklahoma - I like wishbonesooner, who posts here off and on, but a lot of them have adopted the view "Alabama can't beat us" and, of course, they cite as "evidence" the 2014 Sugar Bowl and - my personal favorite - 2003. (Yes, there's actually some clowns who think beating a 4-9 team by 7 points using a fake punt is proof of something).
USC when they were good, not so much fun now (and we pancaked them with a true freshman in his first game).
Nebraska maybe......
"Hate" is basically code for "team I don't like because they beat us."
I mean, we really haven't had that problem at Alabama in a decade......