The young Bomber was drafted to Tullamarine as the 46th overall pick in the 2021 National Draft and would play 36 VFL games over two years with the club.
McBride, a recruit from Ireland on a rookie contract, would not feature for the Bombers across his four years at Essendon. He would have his category B rookie contract extended for the 2023 season following an exemption by the AFL.
Montgomerie was a rookie draft selection for the Bombers last year out of the SANFL as a mature-aged recruit.
He would show strong signs as a key defender at VFL level, but would not manage to break into the Bombers' senior side.
“The three players have been terrific club people and handled the news today with great professionalism," Bombers performance boss Daniel McPherson said in a club statement.
"We wish them all the best for their future careers, and they will always be welcome back at Essendon."
Essendon are believed to have notified contracted swingman James Stewart his time with the club is also up, however the Bombers are yet to comment on the call.