These are my ideas for a few Justice League movies. These movies are part of my DCCU, which you can find in my blog posts page. I think these are good ideas, IN MY OPINION! Feel free to comment!
Justice League - Volume 0: Destiny
A reboot of the "previous DCCU" films, in a new alternate reality where Earth's greatest heroes - Batman, Superman, Wonder Woman, Aquaman, The Flash and Green Lantern - are reimagined as young adults. When an alien robot Brainiac arrives with plans for the six, they find themselves working together and must fulfill their destinies and become the Justice League.
Justice League - Volume 1: Genesis
The world's greatest heroes Superman, Batman, Wonder Woman, Aquaman, The Flash and Green Lantern struggle with their reputations and places as superheroes in the modern world. However, when their arch-enemies and a familar enemy band together to take the League and take over Earth, they must prove to the world that they are needed in this new era as defenders of the Earth.
Justice League - Volume 2: Apocalypse
The Justice League investigates a sighting of a mysterious portal in Metropolis that leads them to the hellish planet Apokolips, ruled by the villainous Darkseid. When they discovers his plans for domination of the entire galaxy and innocent humanoid aliens imprisoned by Darkseid, they must stop Darkseid's forces from crossing over to Earth by fighting alongside their new allies. However, it becomes clear that Darkseid's plans are most sinister than they appear.
Justice League - Volume 3: Unity
When Darkseid and Braniac, revealed to be working together, in the last film, go ahead with their plans to dominate the galaxy. It is up to the newly explaned Justice League to prevent their them from invading Earth and soon the entire galaxy.
After the deaths of some their own members, including Superman, the remaining Justice League must prevent further invasion of Earth by Brainiac's forces. As the world has lost hope, the Justice League strive to save Earth for the future of mankind or else there will indeed be no hope left on Earth.
Justice League - Volume 4: War
A loose adaptation of The Dark Knight Returns. An older Justice League has disbanded, now that there are no longer any large threats to Earth. However, a split between Batman and Superman, causing the Justice League to reunite in a war that will change the world.
The epic finale of the DCCU. After the infamous war between Batman and Superman has caused chaos around the world, so much chaos that the remaining Justice League members attempt to travel back in time to prevent the war, only find that they must do the unthinkable to put the world back to the way it was.