The only playoff game that ESPN was awarded this (just concluded) season, Indy at Houston, was simulcast on ABC.
https://programminginsider.com/2018-19-nfl-playoffs-wild-card-weekend-tv-and-announcer-schedule/
I think technically, ABC is considered to have a contract with the NFL, because they are part of the same "family" with ESPN. However, it is also true that the Super Bowl rotation is limited to the networks that produce over-the-air telecasts (CBS, NBC and Fox).