Reggie Miller, one of the best shooters in NBA history, spent his entire career playing for the Indiana Pacers. Throughout his time in Indy, the most 3s the Pacers hit in a game was just 14.
It took until 2008 for the Pacers to have a game in which the squad hit 15 threes. It finally happened on March 21st of that year, when the Pacers rolled out a starting 5 of Flip Murray, Danny Granger, Mike Dunleavy, Troy Murphy, and Jeff Foster. That group ended up hitting 16 on a red-hot shooting night.
Since then, as the NBA has shifted to a far more three-point heavy environment, the Pacers have made 15 or more 3s on 22 occasions, with half of them coming since the start of 2017.