The All-American did an interesting piece today that looks at every CFP Top 25 from each year of the playoff (Note: the Athletic is a subscription site, so I'll only post some snippets rather than whole paragraphs.  But you should definitely subscribe if you don't already, that place is great.)

Fast facts:

• Ohio State, Alabama and Clemson are the only schools to appear in every single ranking
• If you inverse-weight the rankings (ie, 25 points for #1, 24 points for #2) the all-time top five is Bama, OSU, Clemson, Oklahoma, TCU
• The eventual national champion has been ranked #1 for a grand total of two weeks in the entire history of the playoff (Bama in the third and fourth updates last year)
• 60 FBS teams have shown up at least once 
• 16 P5 teams have never made a list - most are the doormats you could guess (Purdue, Wake Forest, etc), but this list also includes our friends in orange - Texas

(Mod Edit)