Ohio State (winners of the team most often on the cusp award)
Every year of the CFP so far:
2014:
Ohio State was one of three "on the cusp" teams with one loss and a P5 Championship or co-championship along with Baylor and TCU from the B12. Ohio State got in at #4 while Baylor and TCU were left out as #5 and #6 respectively.
2015:
As a one-loss non-champion Ohio State didn't have THAT strong of an argument but most (or all) computer rankings had the Buckeyes (11-1, no CG) ahead of the Hawkeyes (12-1, lost CG), the Trees (11-2), and even that Spartans (12-1, B1G Champs) despite Ohio State's loss to MSU.
2016:
The Buckeyes somewhat controversially got in at 11-1 with no CG appearance and ahead of an 11-2 Penn State team that beat the Buckeyes H2H and won the B1G. The problem for the Nittany Lions was that they had two losses and both of them were bad (Pitt because they were a mediocre team, Michigan because PSU wasn't competitive).
2017:
The Buckeyes got back to and won the B1GCG yet finished behind an 11-1 Bama team that had missed the SECCG. The problem for the Buckeyes was that they had two losses. The 31-16 early OOC loss to Oklahoma wasn't bad (OU was a CFP team) but the mid-season blowout loss in Iowa City was ugly.
2018:
The Buckeyes won the second consecutive B1GCG and finished with just one loss but found themselves on the outside looking in anyway. The problem was that there were three undefeated P5 teams (Bama, Clemson, ND) and another 1-loss P5 Champ (OU) ahead of Ohio State. Oklahoma's loss was better (close vs TX) and they avenged it in their CG.
So in five years of the CFP's existence the Buckeyes have NEVER been clearly in nor clearly out. They have been in the debate range every single year.