In seven years of the College Football Playoff era, 11 different programs have taken part and four different teams have won the title. But the team that has won three of the seven titles has also now produced the single best team of the era. Let's rank all 28 to date (and also the 10 best teams to miss the playoff.)
I derived this list, as I usually do, through a combination of numbers and my own personal opinions. I started out by ordering teams according to their SP+ percentile ratings, then adjusted for actual CFP performance and any other criteria I felt like including.
No. 28 to No. 15

28. 2015 Michigan State (12-2)
CFP result: lost to Alabama, 38-0
Mark Dantonio's 2015 Spartans are definitive proof that the committee is picking the four "most deserving" teams more than the "best"; MSU was definitively the former and in no way the latter. The Spartans finished 18th in FPI and 20th in SP+ but beat a dynamite Ohio State and outlasted unbeaten Iowa to win the Big Ten. Then they did exactly what was expected of them against Alabama in the Cotton Bowl: lost big.

27. 2018 Notre Dame (12-1)
CFP result: lost to Clemson, 30-3
An unbeaten Power 5 (or power conference-adjacent) team will almost always make the CFP, and the Fighting Irish earned their spot with increasingly dominant wins over quality Michigan, Stanford and Syracuse teams. Their defense was solid and exciting (10th in defensive SP+), but their offensive limitations were made crystal clear when they had to face a peaking Clemson squad in the Cotton Bowl. The game was tied after one quarter, but it got much, much worse from there.

26. 2020 Notre Dame (10-2)
CFP result: Lost to Alabama, 31-14
For most of three months, it felt as if this Notre Dame team was different than the one that got blown out by Clemson in the CFP in 2018 or blown out by Alabama in the BCS Championship in 2012. The Irish beat a Trevor Lawrence-less Clemson in overtime and proved physical, mature and adaptable in starting 10-0. But in their final two games, against a full-strength Clemson in the ACC Championship and Alabama in the Rose Bowl semifinals, the Irish got their doors blown off. They were outscored 65-24, and while they managed to keep Alabama within 17 points (31-14), it was with a strategy that almost seemed designed to lose by the smallest possible margin.

25. 2019 Oklahoma (12-2)
CFP result: lost to LSU, 63-28
After three years at No. 1, Lincoln Riley's Sooners ranked only third in offensive SP+, and the defense wasn't good enough to make up for this smidgen of offensive mortality. They rolled to 7-0 but stumbled against Kansas State and eked out four tight wins in their final five games. That was enough to earn the Sooners their fourth CFP appearance in five years, but they got destroyed in the Peach Bowl.

24. 2016 Ohio State (11-2)
CFP result: lost to Clemson, 31-0
After what might have been Urban Meyer's most talented Ohio State team missed the CFP in 2015, the most offensively limited one made it the next year. The Buckeyes ranked just 32nd in offensive SP+. And although their defense was able to hold Deshaun Watson and Clemson to just two touchdowns in the Tigers' first 10 drives, Ohio State couldn't mount a drive of even 30 yards until late in an embarrassing shutout loss.

23. 2015 Oklahoma (11-2)
CFP result: lost to Clemson, 37-17
Bob Stoops' Sooners headed into 2015 with a new offensive coordinator (Lincoln Riley) and a transfer quarterback (Baker Mayfield), and after a disappointing 2014, OU reignited. The Sooners won a loaded Big 12 and were 3.5-point favorites against Clemson in the Orange Bowl. They even took a 17-16 lead into halftime. Clemson shifted into fifth gear in the second half, however, and the Sooners would soon be relegated to Mostly Annual Semifinalist status.

22. 2014 Florida State (13-1)
CFP result: lost to Oregon, 59-20
The Seminoles returned lots of key figures from their 2013 national title romp, but they had to eke out tight win after tight win -- seven one-score games in all. While the BCS would have given us a Bama-FSU title game that year, the CFP gave the Noles the No. 3 seed and sent them to the Rose Bowl, where a 34-0 Ducks run ended FSU's 29-game winning streak in stark fashion.

21. 2018 Oklahoma (12-2)
CFP result: lost to Alabama, 45-34
OU lost Baker Mayfield but somehow improved offensively. Kyler Murray threw for 4,361 yards and rushed for 1,001, and the Sooners topped 45 points 10 times. The defense, however, was dreck. Lincoln Riley fired coordinator Mike Stoops six games in, but the Sooners allowed 44 points per game over their final six contests and gave up 31 first-half points to Alabama in the Orange Bowl. That was too much for even Murray to overcome.

20. 2017 Clemson (12-2)
CFP result: lost to Alabama, 24-6
You know your program is in great shape when "transition year" means "only making the CFP semis." The Tigers boasted perhaps the best defense of the Dabo Swinney era, but Deshaun Watson was gone, and Trevor Lawrence wouldn't arrive in town for another year. Clemson was too good for the rest of the ACC -- upset loss to Syracuse aside -- but it gained just 188 yards against Alabama in the Sugar Bowl, bowing out slightly earlier than normal.

19. 2016 Washington (12-2)
CFP result: lost to Alabama, 24-7
The Chris Petersen era peaked in Seattle with a romp through 2016. Washington sent a message by beating a top-20 Stanford squad by 28 points in September, then finished up by felling Colorado by 31 in the Pac-12 championship game. The Huskies' elite defense, fourth in defensive SP+ and led by Budda Baker and Greg Gaines, mostly controlled Alabama in the Peach Bowl too; Washington trailed just 10-7 late in the first half before a Ryan Anderson pick-six changed the game.

18. 2020 Clemson (10-2)
CFP result: lost to Ohio State, 49-28
It's hard to properly grade a team that was without its star quarterback for one of its two losses (Trevor Lawrence vs. Notre Dame). But while this was most of the typical Clemson team -- Lawrence threw for 3,153 yards in just 10 games, Travis Etienne was even more dangerous as a receiver than runner, and the defense was as aggressive as ever -- the Tigers' defense had a bit of a big-play issue at times. And in the Sugar Bowl semifinals, they got dominated in the trenches, which made the biggest difference in a 21-point loss to Ohio State.

17. 2017 Oklahoma (12-2)
CFP result: lost to Georgia, 54-48
After a bumpy start, Lincoln Riley's first Sooners squad found its top gear midway through the season, winning its final six Big 12 games by an average of 23 points, earning Baker Mayfield the Heisman Trophy and surging to a 31-14 first-half lead over Georgia in the Rose Bowl. The Sooners couldn't hold on, though. Georgia came back twice to force overtime, and OU was done in by a blocked field goal and a Sony Michel TD run.

16. 2015 Clemson (14-1)
CFP result: beat Oklahoma, 37-17; lost to Alabama, 45-40
Five years ago, Clemson was still an upstart. Star quarterback Deshaun Watson was healthy and dominant, but these Tigers sneaked up on the college football world, outlasting Notre Dame in an October monsoon and blowing most of an 18-point lead and a 19-point lead against North Carolina before surviving both. In the CFP, the Tigers surged past Oklahoma in the second half and led Bama before succumbing late in maybe the greatest single quarter in CFP history.

15. 2014 Oregon (13-2)
CFP result: beat Florida State, 59-20; lost to Ohio State, 42-20
Marcus Mariota combined 4,454 passing yards with 770 rushing yards and 57 total touchdowns (and duly won the Heisman), and the Ducks handily ranked first in offensive SP+. They tallied 42-plus points in nine straight games and put up 59 on defending national champion FSU ... but weren't able score over the final 20 minutes of the national title game. An overwhelmed Ducks defense couldn't hold Ohio State back.
The 10 best teams that didn't make the CFP
1. 2015 Ohio State (12-1). The Buckeyes returned most of the 2014 title team but alternated between domination and hangover. They blew out 10-win Notre Dame and Michigan, but their 17-14 loss to Michigan State was just enough to keep them out.
2. 2019 Alabama (11-2). It took Joe Burrow's brilliance and some disastrous fortune against Auburn (two pick-sixes and some unlikely field goals) to keep Bama out of the CFP for the first time, but the Crimson Tide also won 11 games by an average of 35 points.
3. 2017 Wisconsin (13-1). The Badgers beat every regular-season opponent by more than a TD and had two late chances to beat Ohio State in the Big Ten championship game but couldn't. Stomping Miami in the Orange Bowl was a decent consolation.
4. 2017 Penn State (11-2). After winning the Big Ten in 2016, James Franklin's next team won eight games by 18-plus points but came up four points short of perfection: a one-point loss to Ohio State and a three-pointer to Michigan State.
5. 2015 Stanford (12-2). After starting with a loss to Northwestern, the Cardinal ripped off 12 wins in 13 games, losing only to Oregon (by two points) and walloping USC in the Pac-12 championship game and Iowa in the Rose Bowl.
6-7. 2014 Baylor (11-2) and 2014 TCU (12-1). Maybe the two most controversial snubs of the CFP era weren't quite as dominant as you might remember -- as Baylor lost to seven-win West Virginia and barely beat four-win Texas Tech, while TCU barely beat WVU and three-win Kansas. But the Bears became the Big 12's One True Champion with a 61-58 thriller over TCU, and the Horned Frogs were the hottest non-Buckeyes team in FBS late, winning their last three games by an average of 48-5.
8. 2018 Georgia (11-3). Kirby Smart's Dawgs responded to its narrow national title miss in 2017 by rolling to an 11-1 record and building a 28-14 advantage on Alabama with 18 minutes left in the SEC championship ... then blowing the lead and laying an egg in the Sugar Bowl.
9. 2016 USC (10-3). The Trojans began the season 1-2, replaced Max Browne with Sam Darnold at quarterback, suffered an unlucky loss to Utah ... and then ripped off nine straight wins, six by at least 18 points.
10. 2017 UCF (13-0). Facing one of the weakest schedules in the country got them ignored by the selection committee, but the Knights won their first 10 games by an average of 28 points and, in the Peach Bowl, topped an Auburn team that had beaten both CFP finalists.
No. 14 to No. 1

14. 2014 Alabama (12-2)
CFP result: lost to Ohio State, 42-35
The 2014 season saw both the dawn of the CFP era and the beginning of the Great Nick Saban Offensive Evolution. He hired Lane Kiffin to modernize a stale offense, and after an early loss to Ole Miss, the Tide won eight straight to earn the No. 1 seed in the first CFP. They jumped out to a 21-6 lead on Ohio State, but three turnovers and a famous Ezekiel Elliott touchdown run did them in.

13. 2017 Georgia (13-2)
CFP result: beat Oklahoma, 54-48; lost to Alabama, 26-23
Kirby Smart's second UGA team all but ended a 37-year national title drought. The Dawgs won in South Bend, Indiana, in September, destroyed all comers in the SEC East and avenged their lone loss with a dominant win over Auburn in the SEC championship tilt. They outlasted Oklahoma in the greatest game in CFP history and had Alabama all but beaten in the championship game ... until Tua Tagovailoa entered the game. Title drought: now 40 years.

12. 2020 Ohio State (7-1)
CFP result: beat Clemson, 49-28; lost to Alabama, 52-24
No team on this list is harder to evaluate. The Buckeyes played only eight games, but in the first seven they won four by at least 21 points, including a 49-28 victory over Trevor Lawrence and Clemson in the semifinals. They lived up to most of their preseason hype and avenged their 2019 semifinal loss to the Tigers. They also lost in the national title game by 28 points. Still, in this year of abbreviated schedules and limited two-deeps, Ohio State was a poster child of sorts, and it looked like most of what it was supposed to be. At least until the final act.

11. 2016 Alabama (14-1)
CFP result: beat Washington, 24-7; lost to Clemson, 35-31
Freshman quarterback Jalen Hurts took over as Alabama's starter; rebuilding season in Tuscaloosa? Hardly. Hurts won SEC Offensive Player of the Year, and the Tide rolled to the CFP final unbeaten and having won only one game by single digits. They couldn't finish the job, though. With star running back Bo Scarbrough hurt, the Alabama offense couldn't stay on the field, and an exhausted defense gave up three late scores to fall to Clemson.
10 and 9. 2019 Ohio State (13-1) and 2019 Clemson (14-1)
CFP result: Clemson beat Ohio State, 29-23, then lost to LSU, 42-25
It was overshadowed by LSU's late-season brilliance, but both the Buckeyes and Tigers were unreal for most of 2019. They went a combined 26-0 in the regular season; 22 of the wins were by at least 24 points, and only one was by single digits. And in the Fiesta Bowl semifinals, they played one of the most even and compelling games in recent college football memory.
Ohio State dominated the early proceedings, going up 16-0 but settling for field goals; that offered Clemson a lifeline, and the Tigers charged back. The second half featured three scores and three lead changes, and after controversy and countless plot twists, Nolan Turner's interception of Justin Fields made the difference. If they'd played 100 times, each team would have won 50.

8. 2015 Alabama (14-1)
CFP result: beat Michigan State, 38-0; beat Clemson, 45-40
The second Saban-Kiffin mashup showed plenty of early flaws. New starting quarterback Jake Coker was shaky early on and briefly got benched, and while the defense was mostly solid, it got torched by Ole Miss in an early loss. But the Tide manhandled No. 2 LSU in early November, and Coker caught fire down the stretch. Thanks in part to a classic surprise onside kick, Bama outlasted Clemson in a title-game thriller.

7. 2014 Ohio State (14-1)
CFP result: beat Alabama, 42-35; beat Oregon, 42-20
The ultimate "peak when you most need to" team. Ranked 16th in the initial CFP rankings, Ohio State kept getting better and rising down the stretch. Needing a huge statement in the Big Ten championship game, the Buckeyes unleashed the hugest statement, beating Wisconsin 59-0 to eke out the No. 4 seed. They then proceeded to beat Bama with a 28-0 run and take down Oregon with a late 21-0 run. Late-arriving? Nope, just in time.

6. 2018 Alabama (14-1)
CFP result: beat Oklahoma, 45-34; lost to Clemson, 44-16
A warning for the 2020 Tide: The 2018 Bama squad was just as good on paper but couldn't clear the final hurdle. The Tide destroyed their first 14 opponents by an average of 48-16, and only Georgia in the SEC championship game offered any resistance (though the Dawgs offered quite a bit). The Tide combined Nick Saban's best offense yet with a top-10 defense ... but they laid the ultimate egg in the CFP finale.

5. 2016 Clemson (14-1)
CFP result: beat Ohio State, 31-0; beat Alabama, 35-31
Clemson nearly lost to Auburn, Troy and Lamar Jackson's Louisville teams early and did lose to Pitt in mid-November. But as has become a Dabo Swinney custom, the Tigers turned into Angry Clemson after their loss, humiliating South Carolina, keeping Virginia Tech mostly at arm's reach and shutting out Ohio State. Trailing Bama by 10 in the final, the Tigers played a nearly perfect fourth quarter, exhausting the Tide defense and scoring the title-winning touchdown with one second remaining.

4. 2017 Alabama (13-1)
CFP result: beat Clemson, 24-6; beat Georgia, 26-23
Bama went scorched-earth during an 11-0 start, but the offense grew rickety late. The Tide barely eked out a CFP bid after a 26-14 loss to Auburn, and they trailed Georgia 13-0 at halftime in the championship game before freshman Tua Tagovailoa tagged in, led Bama on a 20-7 run and -- after the Tide nearly won in regulation -- threw a famous second-and-26 strike to DeVonta Smith to win Nick Saban his sixth national title.

3. 2018 Clemson (15-0)
CFP result: beat Notre Dame, 30-3; beat Alabama, 44-16
Clemson barely survived September unbeaten, needing a two-point conversion stop to escape Texas A&M and a rousing comeback led by backup quarterback Chase Brice to beat Syracuse. But once Trevor Lawrence was healthy and established in the starting lineup, no one had any hope against the Tigers. They beat Florida State by 49, Wake Forest by 60 and Louisville by 61, and they won two CFP games by a combined 74-19. Goodness.

2. 2019 LSU (15-0)
CFP result: beat Oklahoma, 63-28; beat Clemson, 42-25
Lots of coaches through the years have attempted to modernize their offense in the hopes of giving their program a shot in the arm. LSU's 2019 team set the bar impossibly high for any future modernizers. New passing game coordinator Joe Brady added a few extra tricks for quarterback Joe Burrow and his elite skill corps, and Burrow threw for 5,671 yards and 60 touchdowns (!!!). Once LSU's defense got healthy and up to speed late in the year, LSU was untouchable. Ed Orgeron's squad beat Alabama in Tuscaloosa, then won its last six games by an average of 30 points.

1. 2020 Alabama (13-0)
CFP result: beat Notre Dame, 31-14; beat Ohio State, 52-24
The Crimson Tide had the No. 1, 3 and 5 finishers in the Heisman voting. They played one game decided by fewer than 14 points. They bested an SEC-only schedule by an average of 30.2 points per game. Their defense struggled early but allowed only 15 points per game after mid-October. This team will go down as the best Nick Saban team ever and quite possibly the best of the 21st century.
Best team ... from the best coach ... with the best dynasty of the 21st century (at the very least)? Sounds like the best team of the CFP era.