Star Wars: sequel trilogy. The sequel trilogy did not add anything to the saga. You can leave things ending with Return of the Jedi and would loose nothing.Nothing at all.
Batman Forever and Batman and Robin.
Superman 3 and 4. Both movies are so erased that Superman Returns called itself a sequel to Superman 2
Dragon Ball GT. I never felt Dragon Ball Super ever met the greatness of Dragon Ball and Dragon Ball Z, but I will take Super as an apology for GT that is very not canon.
X-Men Apocalypse and Dark Phoenix.
Bring it on Sequels.
The Lion King: Simba's Pride and Lion King 1/2
Aladdin: Return of Jafar and Aladdin and the King of Thieves
Every Terminator film James Cameron never directed.