If you mean traditional 2D/3D then I would recommend Google Play Movies which can be played on Youtube VR app or Oculus Browser. There's also Netflix App I don't use and a few others. Technically Oculus Browser can be used for Amazon Prine and others.
If you mean VR movies then these are scattered all over the place. Some are available directly through Oculus Store (The Limit, Space Explorers, Henry / Crow), some through third party apps like Amaze.