A team has finished a game with 18-6 singles and extra-base hits 16 times since 1897, most recently Boston Red Sox on 6 June 2024. That is about one every 27,687 team-games.
Box score for the most recent one ↗
18-0 18-1 18-2 18-3 18-4 18-5 18-6 18-7 18-8 18-9 18-10 19-0 19-1
The whole distribution — Singles and Extra-Base Hits · All 18 shapes