there is:
https://www.sportsrec.com/ncaa-college-baseball-rules-6709139.html
Selectively and rarely used, but conferences can implement if a double header is scheduled or the game is a travel Sunday.
Conferences can also schedule 7 inning games on the day of a double header or the final day of a conference series.
Go down to the "Differences between NCAA & MLB Rules" paragraph. Mentions the existence of a Mercy Rule in NCAA, with slight variations within divisions, but that most every team adheres to this rule:
https://seatgeek.com/tba/sports/how-does-ncaa-baseball-work/