It's no secret that My Hero Academia is a love letter to the best works of shonen manga that came before it, as well as the world of American superhero comics. Izuku Midoriya is a scrappy underdog hero in a similar vein to Naruto Uzumaki and Monkey D. Luffy on a fundamental level, but My Hero Academia's tributes go deeper than that.
Many times in the story, certain characters, superpowered Quirks or even one-off side characters are clear homages to pop culture from around the world -- mainly shonen manga, comics, cinema and video games. Author Kohei Horikoshi buried many of these tributes deep in his story, and only after a rewatch or reread do some of them become clear.
My Hero Academia's Manga & Anime Easter Eggs
During MHA's Final Exam arc, the sugar-fueled hero Rikido Sato and the ultra-tough Eijiro Kirishima went up against Cementoss, delivering a barrage of rapid punches to break through their teacher's concrete barriers. The flurry of punches, combined with their clear "ora ora ora!" cries, is a clear tribute to the famous Star Platinum of JoJo's Bizarre Adventure fame, when antihero Jotaro Kujo delivers a beatdown.
During Season 4's climax, the new #1 Pro Hero Endeavor was struggling against the mighty Hooded Nomu, and nearby civilians were rapidly losing faith -- except one. An excitable youth who clearly resembled Fairy Tail's Natsu Dragneel stood out in the crowd, loudly and desperately urging the people to cheer on the flame hero. The original Natsu is a fire-based fighter, helping solidify the reference.
My Hero Academia's Star Wars Easter Eggs
MHA author Kohei Horikoshi clearly adores George Lucas' space adventure in a galaxy far, far away. The retired Pro Hero Gran Torino is modeled after Yoda, being a petite and wise old man who once taught the protagonist's own teacher (All Might vs Obi-Wan Kenobi). Gran Torino posed as a goofy and clueless old fellow at first but soon revealed his true brilliance, just as Yoda did to Luke Skywalker.
The dastardly All For One is the new Darth Vader, being a powerful villain who suffered serious injuries in the past and now relies on life support tech -- complete with a scary black mask -- to survive. They also have deep, imposing voices, and they both inspired later villains: Tomura Shigaraki and Kylo Ren.
An even subtler Star Wars reference is the Tokyo ward Hosu City, named after the ice planet Hoth.
My Hero Academia's DC Comics Easter Egg
Shota Aizawa is loosely similar to the caped crusader Batman, being resourceful and tactically brilliant heroes who rely on gadgets, stealth and investigative skills to capture villains rather than brute force. Both have dark outfits as well. This Batman theme is even clearer when Aizawa is around Ms. Joke, whose colorful outfit and laugh-based Quirk make her like the infamous Joker. The two characters certainly have clashing personalities and worldviews, but unlike the original Batman and Joker, Aizawa and Ms. Joke get along well and understand one another.
My Hero Academia's Marvel Comics Easter Eggs
The tape hero Hanta Sero is My Hero Academia's version of Spider-Man, creating long, sticky strands of tape from his elbows to tie up villains, form webs and even swing around from the rooftops. All Might is a combination of Superman and Captain America with his invincible body, radiant charisma and flamboyant USA theme. And like Captain America, he is humble enough to pass on his cape to another hero, Izuku. This is similar to Steve Rogers passing his legacy on to Sam Wilson.
Many X-Men characters are referenced as well, such as Cyclops in the form of the Navel Laser-shooting Yuga Aoyama. Jurota Shishida, meanwhile, is a rough analog for Hank McCoy/Beast, a burly and furry brute with a surprisingly sharp mind behind the wheel. Tetsutetsu Tetsutetsu, who can harden his skin into shiny steel, is like a junior version of the X-Men hero Colossus.
My Hero Academia's Shovel Knight Easter Egg
A minor background character in My Hero Academia Chapter 271 seems to pay tribute to the Treasure Knight character in the Shovel Knight games, with some alternations to avoid potential copyright issues. This character is visible in the background during a battle between Hawks, Fumikage Tokoyami and Dabi, but didn't play much of a role. Not all Easter eggs have to play a major part like Gran Torino or Eraser Head. Some visual tributes are just a passing joke in good fun, and that was clearly the case with this Shovel Knight tribute. The Treasure Knight certainly gets around.