Thor: Ragnarok is the second-to-last Marvel Cinematic Universe entry until the long-awaited Avengers: Infinity War, and as such it has a lot to do to help move the larger MCU story forward. These 13 Marvel Easter Eggs in Thor: Ragnarok plant the seeds for the upcoming Avengers vs. Thor showdown, while also winking back to the past. In other words: it's just the right amount of Marvel nostalgia and MCU teasers.
Ragnarok is the third, and potentially final, Thor film, and the movie takes place entirely in another galaxy. In other words, it's far, far away from the rest of the MCU, not to mention the reach of the Sokovia Accords, S.H.I.E.L.D., or the Avengers initiative. Unlike Spider-Man in Spider-Man: Homecoming, Thor is pretty much doing his own thing this time around, which means Marvel Easter Eggs in Thor: Ragnarok are fewer and farther between. However, that doesn't mean they're not super important. With less than a year to go before Infinity War hits theaters, the MCU has a lot to set up before diving into the biggest battle the Avengers have ever seen. For the most part, that means setting up the quest for the Infinity Stones, teasing Infinity War villain Thanos (who wants the Infinity Stones), and establishing the relationships between the Avengers.
Warning: the Marvel Easter Eggs in Thor: Ragnarok contains spoilers. Do not read if you don't want to be spoiled.
Surtur is a big part of Thor: Ragnarok, so he's not exactly an Easter Egg. That said, his position at the end of the movie raises some questions as to his possible future in the MCU. A fire demon capable of destroying entire planets, Surtur survives Ragnarok, which means he could come back to haunt the Avengers later on. (Or potentially be used to defeat Thanos.)
"Sorry Jane dumped you!" That's about all the Jane Foster fans get in Ragnarok. Jane, as played by Natalie Portman, is nowhere to be seen in the most recent Thor film, and it's revealed that she broke up with the God of Thunder. Could it have something to do with the fact that Thor doesn't have a phone or a computer to keep in touch with Earthlings?
In one crucial scene, Hela walks through the vaults of Asgard, throwing what looks like the Infinity Gauntlet to the ground, pronouncing it "Fake!" What Thor and Odin thought was safely in their possession is, as seen in the Age of Ultron post-credits scene, actually on Thanos' hand. This reveal works two fold: it answers the question of how Thanos could have the gauntlet after it was scene in Asgard and also prepares Thor for a very rude awakening when he sees Thanos in possession of the gauntlet.
In a desperate attempt to turn the Hulk back into Bruce Banner, Thor attempts to deliver the "Hey Big Guy" speech, a clear callback to Age of Ultron, when Black Widow uses it to calm the Hulk after a fight. The budding romance between Black Widow and the Hulk is further referenced when her face and video message is the thing that helps him turn back into Bruce Banner. (Fingers crossed for a happy reunion between the two in Infinity War.)
The Thor: Ragnarok mid-credits scene teases the arrival of a very intimidating looking space ship, stopping Thor and Loki who are on their own ship, flying towards Earth. The ship is huge, with multiple wings, and unquestionably intimidating. Unfortunately, it's not explicitly identified in the film. Outlets including Den Of Geek have determined that the ship must belong to Thanos. Admittedly, the ship does resemble some renderings of Thanos' ship Sanctuary II. Thanos intercepting Thor and Loki's ship would make perfect sense: Thanos is looking for Infinity Stones, and it's highly possible Loki has the Tesseract with him. It would also be a great way to lead directly into Infinity War. However, knowing what we know about the expanded planets and galaxies thanks to the Guardians of the Galaxy franchise, the ship could be anything. But that wouldn't be much fun, would it?