Detroit Pistons forward Saddiq Bey exploded on the NBA scene in his rookie season and looked like one of the steals of the draft. He finished with the third most 3-pointers made by a rookie in NBA history, and likely would have broken the record if not for a pandemic-induced abbreviated season. He played just 70 of 72 games and finished just 12 shy of breaking the all-time rookie record set by Donovan Mitchell.
It is worth noting that three rookies, Keegan Murray, Bennedict Mathurin and Jabari Smith Jr., could challenge this if they increase their current pace.