"Principal Morita in Spider-Man: Homecoming has a picture of his grandfather, Jim Morita, one of Cap's Howling Commandos from Captain America: The First Avenger (and both characters are played by Kenneth Choi)."
"Thor's comment after Steve calls Mjolnir in Endgame confirms that he saw Steve was worthy enough to lift the hammer in Age of Ultron."
"In Spider-Man: Far from Home, Peter unknowingly mimics the way Tony interacts with holograms in Iron Man, which gets him a fond look from Happy."
"WandaVision reveals that Jimmy Woo mastered the card trick he asked Scott about in Ant-Man and the Wasp."
"A map in a S.H.I.E.L.D. facility in Iron Man 2 seems to label significant places in both past and future MCU movies."
"Greenland is where Cap crashes the Valkyrie, Malibu is where Tony lives at the time, New Mexico is where Thor's hammer lands, and Wakanda is where T'Challa lives. The other locations are a little unclear. The one on the US East Coast could be New York, a reference to the battle of New York; New Jersey, where Camp Lehigh is; or Virginia, where Bruce Banner becomes the Hulk. The one in Europe could be Norway, where the Tesseract was hidden for a long time, or Sokovia, where the Maximoffs are from."
"Captain America: The Winter Soldier mentions Stephen Strange as a target of Project Insight two years before the release of Doctor Strange."
"Agents of S.H.I.E.L.D. references Wolfgang von Strucker and the fact that he gave Scarlet Witch and Quicksilver their powers, which we saw in the credits of Captain America: The Winter Soldier."
"In Agent Carter, we meet the Stark Labs scientist Anton Vanko, who we learned in Iron Man 2 helped create Stark's arc reactor technology and also fathered Ivan Vanko, aka Whiplash."
"In Captain America: Civil War, Sam interrupts Scott because he still doesn't want Steve to find out Scott beat him in Ant-Man."
"In The Incredible Hulk, we meet a pizza-craving grad student who grows up to become Peter Parker's teacher in Spider-Man: Homecoming."
"In Spider-Man: Homecoming, there's a picture of Bruce Banner in Peter's physics class and a mural of Howard Stark in a stairwell."
"Thor's failed attempt to soothe Hulk in Thor: Ragnarok is a reference to what Natasha does to soothe Hulk in Avengers: Age of Ultron."
"Loki cheering when Hulk smashes Thor in Thor: Ragnarok is a reference to Loki getting similarly smashed in The Avengers."
"A Stark-designed ship in Thor: Ragnarok requires that Thor use the name "Point Break," a reference to Tony using the nickname in The Avengers.'"
"Black Panther's UN speech scene parallels the press conference at the end of Iron Man."
"Marvel Cinematic Universe TV shows have a running joke of messing up that famous Spider-Man quote, "With great power comes great responsibility.""
"In Infinity War, Loki makes a reference to something Tony said to him all the way back in The Avengers, making it clear he's really switched sides."
"The first episode of Agents of S.H.I.E.L.D. casually mentions Project Pegasus, which we later find out was the secret Tesseract experiment that gave Captain Marvel her powers."
"Captain Marvel teases people who saw Captain America: The Winter Soldier by implying Fury will lose his eye by trusting a Coulson lookalike, only for him to actually lose his eye by petting a cat."
"Captain Marvel explains how Fury came up with the Avengers Initiative presented in Iron Man 2, as well as where the name Avengers came from."
"Thor actually takes Thanos's advice from Avengers: Infinity War when he kills him in Endgame."
"Also in Avengers: Endgame, Loki brings back (or maybe originates) his spot-on Captain America impression from Thor: The Dark World."
"Steve gets tired of his own catchphrase after using it through three movies."
"Steve almost re-creates his iconic elevator fight from Winter Soldier in Endgame until he realizes the one thing he could have said to walk out without fighting."
"Thor references the shawarma lunch from the Avengers mid-credits scene in Avengers: Endgame."
"Stan Lee makes his final cameo in the MCU in Endgame, bringing with him some poignant final advice for Tony and Steve."
"This is Stan Lee’s final nod and message to his fans as he, quite literally, drives off into the sunset. He's been digitally de-aged, which means this is likely Stan Lee himself in the '70s rather than a character. His final words, 'Make love, not war,' are both a nod to the Iron Man movies because that’s what Tony did when he stopped making weapons for the military and fell in love with Pepper, as well as parting advice to the First Avenger, who goes back in time at the end to live his life with Peggy Carter. So this scene is Stan’s parting gift in the final Avengers movie, and it's underscored by a bumper sticker with one of his catchphrases: ‘Nuff said."
"James D'Arcy returns in Avengers: Endgame to play Edwin Jarvis, Howard Stark's butler who we first met in Agent Carter."
"Pepper's Rescue Armor in Endgame is the same silvery blue as the gown she picked out for herself as a birthday gift from Tony in the first Iron Man movie."
"Sam finally gets to say "on your left" back to Steve in Endgame after hearing it so much in Winter Soldier."
"Steve finally says "Avengers, assemble" for the first time in Endgame after teasing it in Age of Ultron."
"Peter activates "Instant Kill" again in Endgame, but on purpose this time, unlike when he accidentally activated it in Spider-Man: Homecoming."
"Scott gives Hope a look after she calls Steve "Cap" in Endgame because she teased him throughout Ant-Man and the Wasp for doing the same thing."
"T'Challa uses Clint's name when he asks for the gauntlet in Endgame, revealing that he actually did care when Clint introduced himself in Civil War."
"Tony's last words in Endgame before sacrificing himself to save the world are the same words he ended his first movie with."
"Steve and Tony prove each other wrong one last time in Endgame, years after their big argument in The Avengers."
"Tony sacrifices himself for the greater good to save everyone, proving he's the guy to make the sacrifice play, and Steve is able to wield Thor’s hammer, proving he is worthy and special."
"Harley, Tony's friend from Iron Man 3, attends Tony's funeral in Endgame."
"Morgan asks Happy for cheeseburgers at the funeral, the same thing Tony asked for after escaping his abductors in the first Iron Man."
"Tony's first arc reactor, which Pepper turned into a keepsake in Iron Man, also appears at his funeral."
"Steve and Bucky say goodbye in Endgame the same way they did before Bucky left for war in The First Avenger."
"Steve and Peggy dance in Endgame to the same song that was playing on the stereo when Nick Fury broke into Steve’s apartment in Winter Soldier."
"It's Been a Long, Long Time" was actually released just before the end of World War II, and it was a huge hit after the war ended. The lyrics are about reuniting with a lover after a long time apart.
"Throughout Endgame, Wanda's visions from Age of Ultron all sort of come true."
"In Far from Home, Happy turns on "Back in Black," the song that the Jon Favreau–directed Iron Man opens with, but Peter Parker is too young to recognize who it's by."
"The MCU starts with Tony saying "I am Iron Man" at the end of Iron Man, and Phase Three ends with "Spider-Man's name is Peter Parker" in Spider-Man: Far from Home."
"Both Spider-Man: Homecoming and Spider-Man: Far from Home end with a cut-off "What the f—?""
"The earlier commercials in WandaVision correspond to the pieces of Wanda's story we've seen throughout the MCU."
"The Stark toaster represents the Stark tech that killed Wanda's parents and traumatized her and Pietro. The Strucker watch and Hydra Soak represent Wanda and Pietro turning to Strucker and Hydra to find control only to be experimented on. The Lagos paper towels represent Wanda's failed attempt to contain a bomb in Lagos."'
"But the Nexus commercial from WandaVision predicts the "Nexus events" described in Loki."
"As Monica is walking through the hex barrier in WandaVision, she hears a lot of voices, including Carol repeating something she said in Captain Marvel."
"In Avengers: Infinity War, Vision is in the middle of asking Wanda to stay with him when they're interrupted by a fight, and WandaVision reveals that he was most likely about to show her the property he'd already bought them if she agreed."
"WandaVision includes a lot of references to Wanda's past with Vision. Probably the most heartbreaking is Wanda's "I can't feel you," as she feels Vision's lifeless head, which is a reference to them saying "I just feel you" to each other in Infinity War."
"Batroc calling Sam's new uniform a "bird costume" in Falcon and the Winter Soldier is a reference to the UN calling his old suit the same thing in Civil War."
"Sam says the same thing to Karli in Falcon and the Winter Soldier that Steve said to Bucky in Winter Soldier."
"Bucky sleeping on the floor in The Falcon and the Winter Soldier is a reference to a conversation Steve and Sam had in The Winter Soldier."
"In the Captain America exhibit in The Falcon and the Winter Soldier, there's a wall of documents, many of which appeared in Captain America: The First Avenger."
"Bucky asks John if he's ever jumped on a grenade in Falcon and the Winter Soldier because that's the test Colonel Phillips used in First Avenger to see if Steve had "guts.""
"When Bucky refuses to move his seat up in Falcon and the Winter Soldier, it's payback for Sam not moving his in Civil War."
"In Loki, Loki recycles his iconic "glorious purpose" line from Avengers."
"Loki smashes his cup after finishing his drink in Loki, just like Thor does in Thor."
"Natasha and Clint reference a mission in Budapest in Avengers and Endgame, but we don't find out what the mission was until Black Widow."
"The guy who asks Spider-Man to do a flip in Homecoming is the same guy who livestreams the bus fight in Shang-Chi."
"The tower at Kate's school in Hawkeye is named after Obadiah Stane from Iron Man."
"Yelena lands on the roof in Hawkeye in a pose that's very similar to the one she made fun of in Black Widow."
"Yelena makes macaroni and cheese in Hawkeye, the same food she asked for when she was a child in Black Widow."
Wow... that is like the clickbaitiest title you could have chosen for this.
Interesting yeah okay... but most of those are more than obvious to those who have seen the movies. They add those callbacks, becaue they expect people to get them... except for two or three those are really not hidden at all!
Wanted to say the same thing. I couldn't make it through the whole list because I wasn't being told anything I didn't already know.
Another one on the "obvious" train.