Wyldstyle's introduction, feats of skill, and role in rescuing the prophesied hero is comparable to that of Trinity of The Matrix. The Think Tank is similar in concept to the cells where the Machines put the humans to use them as living batteries. There's also Emmet finally grasping the rules of his universe in the climax.
The location for the Lego Castle theme in this world is referred to as "Middle Zealand".
BIONICLE, LEGO Speed Racer, Fabuland and LEGO Friends get a reference in a blink-and-you'll-miss-it montage explained by Wyldstyle. Some see it as a Take That against these lines because Wyldstyle doesn't deem them worth mentioning by name.
The map of the LEGO universe can be seen in another part of Wyldstyle's Expospeak, containing further references to LEGO themes, such as Atlantis, Pharaoh's Quest, Technic Mecha Cave and Vladek's Realm.
On the other hand Bruce Wayne looks a little psychotic, but he fits right in with the rest of the corporate robots.
At Cloud Cuckooland, Batman is annoyed by a clown and a man in a dino suit. So the Joker and Killer Croc, essentially.
Conversely, the dino suit could be a Shout Out to the T. rex Batman keeps in his Batcave.
During the attack on Cloud Cuckooland, a unicorn runs by on fire. The same thing is witnessed during the climax of Avatar.
The destruction of Cloudcuckooland is also similar to the terrorist attack on the good side of Imaginationland from South Park's Imaginationland trilogy.
Emmet's fall down the black hole marking the edge of the universe resembles the Stargate sequence from 2001: A Space Odyssey. Additionally, Lord Business refers to his flying headquarters as a "black monolith".
The flying monolith also resembles the square ships used by the Vogons when they destroy earth. The Vogons similarly cause panic when they take over communication channels
An extremely subtle reference is slipped in during the climax, shouting out to BrickFilm community. One of the first major BrickFilms (stop-motion movies made out of Lego, no doubt a big inspiration for the film) was ''The Magic Portal'', made sometime in the late 80s. Now, look at the tube that Finn uses to send Emmet back into the Lego world at the end: what's it called? The Magic Portal.
Johnny Thunder's cameo role includes two jokes referencing his Indiana Jones Expy status: An Indy Hat Roll through the portal when Wyldstyle explains how the Master Builders escaped Lord Business's forces and running from a golf ball during the assault on Cloud Cuckooland.
A dolphin chirp is thrown in when Emmet is being booed by the Master Builders (specifically, from a shark that someone threw at him). Dolphins were a Running Gag in Clone High.
The Cleopatra mini-fig waves pom poms when the NBA all-stars are fighting Bad Cop and the micromanagers. Cleo in Clone High was a cheerleader.
The DVD-exclusive short Michelangelo and Lincoln: History Cops has definite shades of Black and Tan from the episode "Film Fest: Tears of a Clone".
The term "Master Builder" is a title given to employees of LEGO whose job entails helping to design new sets and also building large, complex statues out of LEGO bricks, the kind that are commonly displayed at LEGO theme parks and retail stores.
When Wylde Style tells the main character "I found your pants, series is over" (I'm paraphrasing.), it seems like a reference to How I Met Your Mother, a series that ends when the title of the show is answered. Specifically, because directors Lord and Miller wrote for that show.
The vision Emmet receives when he touches the Piece could just as well have been delivered by a Prothean beacon.
In Emmet's brain, they have a vision of Finn that looks an awful lot like Crazy Hand. The premises between the two franchises are similar as well.
When the team infiltrates Lord Business' Tower, Wildstyle tells Emmet that they're in the clear by giving him The Signal
Business uses an army of Robot police, as well as Bad Cop's entire character arc. He starts out with a kind side, only to have it erased by a Corrupt Corporate Executive so that he can be his loyal stooge, before realising that he was being used and dispatched. He then overrides his lawful duties, changes his face to a more benign (albeit a unsettling) one and helps the heroes stop his cruel master.
When Bad Cop rides in on a horse in the Old West, is it a Bad Horse?
Finn The little boy in the live-action portion is a likely homage to the same-named character from Adventure Time about a boy who's constantly living in his imagination (to the point where the viewer never sees the "real world," just the world of Finn's imagination).
The climatic battle bears an extremely strong resemblance to the final climatic battle of the Phineas and Ferb movie (down to having villains extremely obsessed with order taking over the city/Tri-State Area with a horde of flying robots, only to be taken down by an equally large and awesome horde of creations made from people's imaginations).
The large LEGO brick balancing on its corner in Bricksburg is a reference to the Alamo Cube, a piece of public art in New York City.
Even though they were mocking Star Wars with that Millennium Falcon bit, Emmet stopping the bad guy by talking him into making a Heel-Face Turn and believing that he can be good instead of fighting him is comparable to Luke and Vader in Return of the Jedi. Even more so when you know that it is actually representing a son talking to his father.