Just looking at some of the games that might have happened in 2019 in a 12-game playoff.
Top-6 conf champs: LSU (1), Ohio State (2), Clemson (3), Oklahoma (3), Memphis (17), Boise State (19).
Top-6 others: Georgia (5), Oregon (6), Baylor (7), Wisconsin (8), Florida (9), Penn State (10).
Byes: LSU, Ohio State, Clemson, Oklahoma
Round 1 games (with estimated outcomes, just taking highest rank to win):
Georgia (11-2) vs. Boise State (12-1) -> Georgia
Oregon (11-2) vs. Memphis (12-1) -> Oregon
Baylor (11-2) vs. Penn State (10-2) -> Baylor
Wisconsin (10-3) vs. Florida (10-2) -> Wisconsin
Round 2:
LSU vs. Wisconsin -> LSU
Ohio State vs. Baylor -> Ohio State
Clemson vs. Oregon -> Clemson
Oklahoma vs. Georgia -> Oklahoma
Those could have all been some fun games.