https://en.wikipedia.org/wiki/College_football_national_championships_in_NCAA_Division_I_FBS

Utah and UCF both got some national title from some of the computer programs too (Colley Matrix for UCF, Anderson & Hester, Massey, and Wolfe for Utah), although that's obviously meaningless. Utah was also awarded one by some organization, but I forget who.

Keep in mind, I'm not claiming a national title for Utah in 2008. I'm just saying that there have been very few actually unanimous CFB national champions in Division IA, and most of those are recent (out of the 148 years of national champions, there were 13 unanimous champions in the 32 years prior to 1901, when only the Ivy League appears to have been playing CFB, there were 4 between 1901 and the end of WWII, there were 5 between the end of WWII and the beginning of the BCS in 1998, there were 5 unanimous BCS champions, and there have been 3 unanimous champions since the CFP started).