Astro City is just full of references and in-jokes to people, places, and events in its own history. Here are some of the deeper cuts:
The very first issue of Astro City has the Samaritan flying alone in his dreams. The twentieth anniversary issue also focuses on his dreams of flying, only this time Winged Victory is flying alongside him.
In "Thumbtacks & Yarn", one brief story has a man dealing with a snake cult, only to have the Broken Man interrupt and yell at the reader for trying to read the story prematurely. Later, in "The Sky's The Limit", Zootsuit stops two Lizard Folk from trying to attack a young woman — and on the next page, the Broken Man is in the gutters of the page, gesturing silently back to the thwarted attack.
In "Apeman Blues", Sticks' solution to his dilemma involves some of the characters from "On the Sidelines", published two years earlier.
Elliot Mills, the reporter from "The Scoop", reappears from time to time. "The Dark Age" reveals that Mills is the author of Charles' and Royal's story, while the "Astro City Visitor's Guide" includes his article giving a brief history of the city.
Astro City: Astra issue #2 is addressed to Andrew Eisenstein of Fairbanks, Alaska — who was last seen Put on a Bus in "A Little Knowledge".
In "Resistance", the fact-checker who verifies that Louisa's news story is legally safe is Asa Martin, a.k.a.Samaritan.
In the third Blacksad album "Red Soul", Blacksad is sufficiently annoyed when he has to attend a Natalia Wilford Look-A-Like contest when doing bodyguard duty for a rich client. This should only make sense if you've read the first one, and know about his history with the real woman.
We have Mark discovering his powers by throwing the trash bag with a little too much power. Many issues later, we cut to London, England, where a passerby comes by an odd trashbag labeled "Burger Mart"...
Another call back, when William finds out that Mark is Invincible and that he can fly, he asks for what every man wishes he could do. Later on, William finds out who Atom Eve is, and asks for the same thing. The call back? Mark and Eve's response. "This is so gay."
The words Nolan ask of Mark in the 12th issue of the comics become the most significant phrase in the series as it is echoed in the very final 144th issue, in its final pages: "What will you have after five-hundred years?!" as Nolan once asked in his attempt to make Mark go along with his earth conquering plan, reasoning that everything Mark had at that point would be meaningless in his long living life; then many earth and universal changing events later, by the end of the series Mark remembers those words, 500 years later Mark became a great man, who managed to change Nolan's heart, changing the whole viltrumite race into a peaceful one, keeping his own heart in the right place, living happily with Eve and their daughter Terra for 500 years and beyond as the emperor a prosperous world.
At one point in Kick-Ass, Dave's friends decide to invent a new curse, and come up with 'tunk' to refer to a cock and balls; specifically, they intend it to be the male equivalent of 'cunt'. They resolve to drop it into as many conversations as they can. In the last issue of Volume 1, John Genovese is shot in the crotch, and exclaims "He just shot me in the fucking tunk!".
Luther Arkwright: Plenty in the sequel Heart of Empire. One of the most prominent is when Victoria wakes up naked on parallel 00.69.05, walks out in public, and garbs herself in a Union Jack flag. Both the event and the poses calls back to when her father Luther did the same in the royalist camp in The Adventures of Luther Arkwright.
In issue 16 of the comics, in the story "Five Green Vandals", Bubbles dredges up Buttercup's crush on Gangreen Gang leader Ace in the TV episode "Buttercrush". Buttercup is naturally repulsed by it.
Issue #30's "Monkey See, Monkey Dough": Mojo wants to hire Bubbles to clean a device (which she doesn't know is a destruction device), and she instantly brings up how she and her sisters helped Mojo nearly take over Townsville in the movie.
The Emerald City Comic Con exclusive cover for #1 of the official comic has cameos from Mr. Meeseeks, the guy from the Gear Wars, one of the anthropomorphic Pop-Tarts, and Gazorpazorpfield (in the form of a tattoo).
Jerry is shown to still regularly visit "Doofus Rick" in the latter's dimension.
In Issue 39, Rick shares his "special snack" with Morty: the Simple Rick's wafers from "The Ricklantis Mixup". He also comments that "the new ones just don't taste right, like they changed the formula or something", which did indeed happen in that same episode.
When the final enemy of Issue 42 is a sapient dog that none of the Smith-Sanchez family can bring themselves to kill, Rick goes to find Snuffles/Snowball from "Lawnmower Dog" to resolve the problem.
In Issue 56, when various bar patrons are talking about their shared hatred for Rick, one alien angrily notes that he's had to start working in a Plumbus factory to support his family after Rick dismantled the Galactic Federation.
The Brain Spawn are able to turn Leela and Bender into idiots, but it has no effect on Fry. One of the Brain Spawn then recognizes him as the human who thwarted them in "The Day The Earth Stood Stupid".
Fry ends up replacing Edna Krabappel as Bart's teacher because she's sick. Why is she sick? Well, according to Skinner, she ate some undercooked steamed hams the previous night.
In order to defeat the fictional characters invading New New York, the Simpsons summon the giant Homer from the very first issue of their comic book series.
The Tribble seen in Scotty's workshop on Delta Vega in the 2009 film is later brought back, and serves as the primary motivator for the "Truth About Tribbles" storyline, where it causes havoc in San Francisco.
Chekhov's origin story reveals he was responsible for Helmsman McKenna's illness, the same one that meant Sulu had to fill in for him.
In "Boldly Go" issue 2, the crew of the Endeavour analyse where the ship that attacked the Concord is going. Not only is it going to the exact place the Narada first appeared, their scans indicate they share technology and power. Which they would, given "Countdown" revealed the Narada was made using Borg technology.
Star Trek: Untold Voyages: When Krell threatens to attack the Enterprise in "Renewal", Kirk tells him that a new superweapon called the Omegatron, which has the capability of destroying Krell's ship and the other two battle cruisers under his command, was installed aboard the Enterprise during its refit. This is essentially the same as the corbomite bluff that he used successfully against Balok in "The Corbomite Maneuver" and ten Romulan birds-of-prey in "The Deadly Years". However, Krell does not believe him as he is of the opinion that the Federation is too weak and soft to use such a device, especially since it has never made use of the Romulan cloaking device that the Enterprise stole in "The Enterprise Incident". Nevertheless, the Enterprise manages to penetrate Krell's shields and disable his ship by channeling all of its phaser energy through the warp engines. Will Decker previously explained that the phaser systems had been redesigned in this fashion in Star Trek: The Motion Picture.
In #8, it's explained that Rackham Sear has obtained a layout of the Jedi Temple from Bounty Hunter Cad Bane. It was given to Bane by Sidious in "Holocron Heist" the first episode of season 2 of The Clone Wars.
Ezra's quote "I think I'm in love" upon seeing Kanan's old ship reflects the final passage of A New Dawn ("Kanan Jarrus was in love") when Kanan sees The Ghost for the first time.
When the newly formed debate team has their second place win announced in the morning announcements, two boys seated in front of her consider it news that they have one at all, to Sunny's irritation. After they take first in regionals and it's announced again, the same two boys still don't know they have a debate team.
Sunny squints in the Polaroid picture with the second place trophy. She does the same in the newspaper picture with the winning trophy.
Nintendo's German staff released a Yoshi's Story special that contained Anvilicious stories obviously aimed at children, including one where a black Yoshi was subjected to Fantastic Racism. Awesomely, he turned out to be the Yoshi from "Mario im Wunderland" (a ''The Wizard of Oz'' parody published in Club Nintendo five years earlier) who had complained about being green just like the bushes and been turned black by the wizard.
of the official comic has cameos from Mr. Meeseeks, the guy from the Gear Wars, one of the anthropomorphic Pop-Tarts, and Gazorpazorpfield (in the form of a tattoo).