Mullett, 25, played 85 games for the club including 18 this season, while Wagner, 20, played eight senior matches, four of which were in 2017.
“Aaron fought hard for promotion off the rookie list on two occasions early in his career which showed his dedication and perseverance,” North Melbourne’s General Manager of Football, Cameron Joyce said.
“He’s been a fantastic servant of the club for the past seven years and we sincerely hope he can resurrect his AFL career with another club.
“It’s no doubt been frustrating for Corey with injury hampering his progress.
“Both players are young men of great quality and we’d like to thank them for their hard work and efforts during their time at Arden Street.
“We wish them every success for the future.”
Mullett was recruited with pick No.34 in the 2011 Rookie Draft, while Wagner was selected with pick No.41 in the 2015 National Draft.