A team has finished a game with 6-21-0 runs-hits-errors line 2 times since 1897, most recently New York Yankees on 19 April 2001. That is about one every 221,502 team-games.
Box score for the most recent one ↗
6-19-4 6-20-2 6-20-3 6-20-1 6-21-1 6-21-3 6-21-0 6-22-2 6-22-4 6-24-1 6-28-5 7-1-0 7-1-1
The whole distribution — Runs-Hits-Errors Lines · All 18 shapes