5. Dennis Smith Jr.
Dennis Smith Jr. is one player who was drafted by the Dallas Mavericks and not traded on draft night. During the 2017 NBA Draft, Dallas selected Smith Jr. with the ninth pick.
He had a solid rookie year as he was named to the NBA All-Rookie Second Team. In his first season, Smith Jr. averaged 15.2 points per game, 5.2 assists and shot 39.5 percent. He was also the team's second-leading scorer, ahead of Hall of Famer Dirk Nowitzki.
Other accomplishments include him recording a triple-double during his third month of action, as he became the sixth-youngest player In NBA history to record one.
His numbers told a different story sophomore year when he averaged 12.9 points per game. Part of his decline was the draft selection of Luka Doncic.
Smith Jr. was traded midway through the 2018-2019 seasons as the Mavs traded him for Kristaps Porzingis. He would not be the same after that, as injuries and inconsistent play took a toll.
Nothing will ever beat his rookie season though. Smith Jr. was a flashy guard who wasn't afraid to drive to the basket and slam it with authority or create his own shot.
Imagine if Dallas never traded Smith Jr., its possible he and Doncic could have become a dominant duo with time.