Maybe someone will do an Epic Order Edit and put every scene in chronological order.
Let's see, and this is all off the top of my head so I might be getting some things totally wrong and I'm sure I'll be forgetting stuff.
You could start by editing together the origin of the infinity stone scenes with the Collector in the first Guardians and Wong in Endgame.
Then the origin of Wakanda scene from Black Panther.
The opening flashback from Thor the Dark World.
ETA: Hela vs Valkyries from Thor Ragnarok (thanks
@UssGlenn )
The opening flashback from Thor.
The "I'm with you till the end of the line" scene from The Winter Soldier.
The main body of Captain America the First Avenger.
The Agent Carter one shot and show. ( for the sake of my sanity I'm not even thinking about the flashbacks within the show, nor am I considering any of the other shows that were not produced by Marvel Studios.)
Bucky flashbacks from The Winter Soldier.
Flashbacks with Ego and Meredith Quill take place in 1980.
All flashbacks with Hank and Janet Pym.
Peter Quill is abducted from Earth in 1988.
The flashbacks in Captain Marvel and the opening scene flashbacks in Ant-Man take place in 1989.
The death of Howard Stark flashbacks in Civil War take place in 1991.
Killmonger flashbacks from Black Panther
Thanos adopts Gamora, Natasha's time in Ohio and the main body of Captain Marvel all happen in 1995.
The opening flashback of Iron Man 3 takes place in 1999.
Iron Man ( the theoretical mega cut would have to start at the "18 hours earlier" portion, then do the opening sequence, and then continue from there.)
The next 3, Iron Man 2, The Incredible Hulk and the main body of Thor take place during the same week 6 months later.
The one shots were all produced by Marvel Studios and the one shot A Funny Thing Happened on the Way to Thor's Hammer took place during Coulson's journey from Iron Man 2 to Thor, and The Consultant takes place not much after the Incredible Hulk and is followed by the frame from Captain America the First Avenger.
The Avengers finishes out phase-one, with the one shot Item 47 providing an epilogue.
Then there is the main body of Iron Man 3, the final one shot All Hail The King, and the main body of Thor Dark World followed by Guardians of the Galaxy 1 and 2 ( with a small exception from GotG2 to be noted later).
The Bucky flashbacks of the Falcon and the Winter Soldier.
The non flashbacks sections of Captain America the Winter Soldier and all but the end credits sequence of Age of Ultron. The rest of Antman closes out phase 2.
Ugh. Posted prematurely. Continue to next post.