Rakell made his Penguins debut against the Columbus Blue Jackets on Tuesday.
Aston-Reese scored 11 points (two goals, nine assists) in 52 games this season. The 27-year-old signed a one-year contract with the Penguins on Aug. 5, 2021, and can become an unrestricted free agent after the season.
Signed by Pittsburgh as an undrafted free agent on March 14, 2017, Aston-Reese has scored 62 points (29 goals, 33 assists) in 213 regular-season games and four points (one goal, three assists) in 23 playoff games.
"Zach Aston-Reese has been a terrific Penguin, and we thank him for everything he's done for the organization," Hextall said. "Dom Simon as well."
Simon scored nine points (three goals, six assists) in 55 games this season. The 27-year-old signed a one-year contract with the Penguins on July 28, 2021 and can become an unrestricted free agent after the season.
Selected by the Pittsburgh Penguins in the fifth round (No. 137) of the 2015 NHL Draft, Simon has scored 73 points (22 goals, 51 assists) in 239 regular-season games with the Penguins and Calgary Flames and four assists in 12 playoff games.
Clang has not played in the NHL. The 19-year-old was selected in the third round (No. 77) of the 2020 NHL Draft and played for Rogle BK of the Swedish Hockey League, the top professional league in Sweden this season.
Anaheim (27-27-11) was seven points behind the Vegas Golden Knights for the second wild card into the Stanley Cup Playoffs from the Western Conference.
The Ducks traded defenseman Hampus Lindholm to the Boston Bruins and forward Nicolas Deslauriers to the Minnesota Wild on Saturday.
"My goal at the end of it was to try and get some young players along with draft picks, picks that were kind of more advanced in their development," said Ducks general manager Pat Verbeek, who was hired Feb. 3. "And I'm very happy with how it turned out with getting those young players and now accumulating some draft picks."
NHL.com independent correspondents Wes Crosby and Dan Arritt contributed to this report