Despite plenty of bad edits and inconsistencies within the plot, Endgame is a favorite among MCU fans mostly because of the time travel aspect. While the time travel rules are one of the biggest points of contention, fans loved the time heist and are curious about other potential destinations the Avengers considered.
With the six Infinity Stones showing up in a vast majority of Infinity Saga films, the possibilities are nearly endless. Though it's important to note that most of these options are from an outside perspective— many of the characters are probably unaware of how certain events played out and would need some insider information for these to work.
10 The Alternate Locations Shown On Screen
The dates in question were November 2009, May 2012, and January 2988 B.C. The year 2988 jumps out as the year Bor defeated the Dark Elves and hid the Aether away. The Avengers considered this year for the Reality Stone, but it would have been much more difficult given the circumstances.
However, the other two dates don't hold any obviously special significance within the MCU. With Tony's connections to the military and S.H.I.E.L.D. it's possible he may have known about when and where the Tesseract was being transported— but that hasn't been confirmed.
9 Asgard Was Home To The Reality Stone & Space Stone For A Short Period
The writers' original idea was to have Tony join Thor and Rocket on Asgard to find the Tesseract while Rocket and Thor found the Aether. Tony was supposed to fight Heimdall and "Fat Thor" was supposed to fight his younger, more in-shape self; but that all changed, and fans got Cap vs Cap.
This would have been an interesting alternate mission, but at the end of the day, it made more sense for Tony to go with Steve. Had events played out this way, Thor may not have got to talk with his mother, which ended up being a significant part of his arc.
8 The Collector (Very Briefly) Possessed The Reality Stone & Power Stone
Despite Tivan having two Stones to take, this was actually a rejected premise for Endgame. Additionally, Captain Marvel was supposed to be part of the team tasked with going to Knowhere. However, the Russo brothers didn't want to come back to another Infinity War setting after already going back to Vormir.
It would have been Captain Marvel, Rhodey, and Nebula to retrieve the Power Stone and Reality Stone from the Collector while Nat and Clint went to Vormir. Team Cap would have to find the Reality Stone first and hope one of them could figure out how to use it to apprehend the Power Stone before Carina blew herself up.
7 There Is A Convoluted Way To Get Three Stones During WWII
This scenario is a bit of a stretch, but in theory, the Avengers could retrieve the Space Stone, Time Stone, and Soul Stone during World War II. Unfortunately, someone would still have to die for the Soul Stone, and the best suited for the task would be Ant-Man and the Wasp (assuming she didn't dust in this scenario). They would hide out on Red Skull's ship, go through the Tesseract portal with him to Vormir, and presumably have a similar fight to the one Nat and Clint had.
Captain Marvel would be on the outside of the ship, ready to catch the Tesseract when it burned through the aircraft. Then they would simply need to convince the Ancient One, though it might be a bit more difficult considering how early they would be this time around.
6 The Mind Stone & Time Stone Were Available During Age Of Ultron
During the events of Age of Ultron, there is a brief period where the Avengers are in possession of the Mind Stone in New York before Ultron attacks them and escapes with the scepter. This would be a fairly simple mission to pull off: Just sneak into the lab portion of Avengers' Tower during the party and snag the scepter while J.A.R.V.I.S. was busy with a nascent Ultron.
Then, like most other attempts to retrieve the Time Stone, the Avengers would need to commandeer it from the Ancient One. Hopefully, they would be able to convince her to hand it over by saying the right thing like Banner did.
5 There Are Three Stones On Earth During Thor: The Dark World
This mission would have been a difficult one to maneuver. The best chance for the Avengers to commandeer the Reality Stone would be to swoop in and extract it from Jane Foster just after she returned to Earth but before Thor arrives to take her to Asgard— which is a tight window.
Once the Reality Stone was secured, the mission wouldn't get any easier. They would not only have to find the scepter with the Mind Stone— presumably somewhere in Eastern Europe— but would also likely have to fight through scores of Hydra soldiers to get it. Additionally, they would have to convince the Ancient One to hand over the Time Stone (in New York), making the trip a global adventure.
4 2012, But A Bit Earlier With A Focus On Loki
If the Avengers weren't concerned with making a splash in the timeline, they could have ambushed Loki during or shortly after his assault on the Project P.E.G.A.S.U.S. base. Loki would have been in possession of both the Mind Stone and Space Stone a few days before the Chitauri invasion even begun.
After dealing with Loki, the Avengers would then need to speak with the Ancient One, which seems to be the only way to get the Time Stone regardless of which year they travel to. This option probably would have been a bit easier than the actual plan— since that one ended up failing— but would have required more meddling which may have changed the TVA's mind about being so forgiving.
3 The TVA Has A Lot Of Extras Lying Around
While the only person who actually knows about the TVA is Loki, it would have been crazy to introduce the TVA in Endgame and have the Avengers steal all of Casey's assorted Stones— and perhaps the Honus Wagner card. However, there would be no guarantee that any of the Stones would have worked since their original timelines were pruned.
The Stones don't work at the TVA, and comic book precedent suggests that the Infinity Stones would only work in the universe they were forged in— that is, from the timeline they were created in. This mission wouldn't have made much sense, and the TVA's introduction in Loki was excellent, so it's probably for the best the Avengers don't know about it.
2 There Is A Tricky Way To Get The Time Stone & Space Stone In Ragnarok
This is another option that isn't a very convenient one, but it is technically possible. It would probably be much more difficult to apprehend the Time Stone from Strange than the Ancient One because he probably wouldn't believe the story they told him. Or, he might already know about everything and hand it over willingly. It could literally go either way.
However, that would be the easy part. After commandeering the Time Stone, the team would have to somehow sneak into the Bifrost portal that Thor, Loki, and Hela had just jumped into. This would presumably be a job for Ant-Man (and maybe Rocket) as he would be able to sneak through the portal undetected to find the Tesseract on Asgard, probably.
1 It Could Have Been Advantageous To Blindside Thanos On Vormir
It would have been a huge gamble to try and ambush Thanos after he had just acquired the Soul Stone, but if they could have pulled it off the Avengers would have had four Stones in one go. One advantage is that Thanos wouldn't be expecting it, and if enough heroes arrived together they could probably take him down.
While he would have four Stones at his disposal, Thanos would also be distraught over having just killed his favorite daughter for the Soul Stone. If the Avengers could somehow exploit that, and make sure to bring Captain Marvel along, they stand a pretty solid chance of swiping four Stones at once. Most importantly, Natasha would still be alive.