I plan to do an MCU list in the future, but that requires a lot of thought and consideration on which are the best. So for now, I'll do one for DC. From best to worst in my opinion.
P.S this list will be updated when certain movies are released (if I remember). The Snyder cut will be added as well instead of removing the Justice League (if it becomes its own film to add to the list), that's because I am for sure Zack's version will be better than Joss's version. That's not to say that it will be perfect but its a good guess to assume the original director's vision will be an improvement (even if it is Zack Snyder).
Update: Zack Snyder's cut has been added