The Iowa rivalry is a joke. It's always felt contrived. They've never won anything in most of our lifetimes and their real rival is ISU, which is a much better fit for them.
OU was great but it was many many moons ago when it actually meant anything. Their real rival is Texas.
Not sure why UCLA is being mentioned. Their real rival is USC.
Colorado would be great...border state, some real history (70 or so games) and serious hatred there. They don't really have one either as CSU is too spare of a program to really count. They've at least won a NC and a Heisman in the modern football era. With Deion, they're at least relevant again, but who knows how long that lasts. TBD whether they really want to get back to taking football seriously again. And, since they're not in conference, it's all probably a mute point.
That leaves PSU for me. I don't think they really have one. Will take some time as 18 games is not a lot of history. Maybe Rhule can help that along.