Luna's idol, Mick Swagger, is an obvious parody of Mick Jagger.
Lincoln owns a green-colored toy of King Ghidorah in his bedroom. He also has a robot toy reminiscent of the infamous Mazinger Z as well, and a toy of Robbie the Robot too.
One of the houses that shows up often in the background looks similar to the Griffin's household.
Luna has a tendency to make references to classic rock songs:
Luna saying "For those about to rock" in "No Guts, No Glori" was a reference to the AC/DC song "For Those About To Rock".
Luna told Lincoln "You can't always get what you want, bro" in "Project Loud House". It's a reference to The Rolling Stones' song "You Can't Always Get What You Want".
Luna saying "Yeah, every little thing is gonna be alright" references Bob Marley's "Three Little Birds".
Luna's "Woah, dude. Looks like pool's out for summer" line from "Linc or Swim" references Alice Cooper's "School's Out".
Luna once sung the line "Walk this way" in "Changing Baby", which comes from "Walk This Way" by Aerosmith.
Luna has two in "Hand-Me-Downer". When she gave Lincoln her broken guitar, she said "Here you go, bro. All it needs is love. Love is all it needs", referencing "All You Need Is Love" by The Beatles. When referring to a bike Luna said "'Had to do some work on it. But then it was ride Sally ride". This references Wilson Pickett's "Mustang Sally".
One reference that got past the censors was her reference to "Highway to Hell" by AC/DC. In "Butterfly Effect" Luna tells Lincoln "Check it, bro. I uploaded a song about our family going down the highway to—*computer noise* hello! I just got 50 more hits."
In "Chores and Peace", all the sisters get in on the song reference however it's Luna that led them. It's a reference to Edwin Starr's "War".
Luna: Chores, huh, what are they good for?
Everyone: Absolutely nothing! Say it again!
When she, Lincoln, and Clyde get arrested in "For Bros About To Rock" Luna says "Sorry bro. I fought the law and the law won", referencing "I Fought The Law" written by Sonny Curtis. In the same scene she says "I know it's only rock-n-roll, but I like it". That references "It's Only Rock 'N Roll (But I Like It)" by The Rolling Stones.
Luna's come back "Yeah, dream on" in "It's A Loud, Loud, Loud, Loud House" references Aerosmith's "Dream On".
Luna singing "Time for me to go solo" in "House Music" references "Time For Me To Fly" by REO Speedwagon.
When Luna begs to Lisa in "April Fools Rules" she says "Please, gimme shelter!", referencing The Rolling Stones' "Gimme Shelter". Later on, Luna says "She's a black magic woman, dude", referring to Luan, which references "Black Magic Woman" by Santana.
In "Cereal Offender" Luna says over the microphone "For those about to shop: I salute you!", referencing "For Those About To Rock (We Salute You)" by AC/DC.
In "Raw Deal" Luna tells Lincoln "The vending machine gave me an extra bag of chips! The best things in life are free, bro", which references Ray Henderson's "The Best Things In Life Are Free".
In "'L' for Love", Luna said "Dream on, Lunes, you're the owner of a lonely heart", referencing Yes' "Owner Of A Lonely Heart" as well as possibly "Dream On" by Aerosmith.
In "Tricked" Luna complimented Lucy, "Halloween is kinda crazy with a spooky little girl like you!" referencing 60s song "Spooky" by Classics IV
In "Future Tense", Luna screams "We don't need no education!" when her parents sign her up for classes at a community college. This references the song "Another Brick In The Wall (Part 2)" by Pink Floyd.
Lisa gives Leni an acne cream that turns her skin blue. She then offers her a swelling potion before Lincoln tests it out first, referencing "Willy Wonka & the Chocolate Factory".
106a — Sound of Silence
The title can only be referencing the famous song of the same name by Simon & Garfunkel.
When Lincoln comes back in the house after rolling around in the trash, a soda bottle with ZOSO printed on it can be seen stuck to his foot.
Lincoln shouts "TAKE MY MONEY!" at a delivery drone, even tossing an absurd amount of cash at it, referencing the meme from "Futurama".
The stories of Lola's extreme vengeance on her sisters include parodies of the "horse head" scene from The Godfather and the "bunny boiler" scene from Fatal Attraction.
106b — Space Invader
The title card parodies the gameplay of Space Invaders, with 8-bit music to match.
At the beginning of the episode, Lincoln (while dressed up as Ace Savvy) is doing the Moonwalk Dance on bed, complete with him yelling at the end just like the late Michael Jackson did before doing that in his Live Performances (albeit for the latter, twice in a row).
111a — Butterfly Effect
Lola gets hit in the face with a soccer ball, resulting in a swollen nose.
Levi, Lisa's male counterpart, appears to be a more clear reference to Dexter.
In the brief shot where a colorless background to the inside of Loki and Loni's room can be seen, there's what appears to be a poster of the cover of Pink Floyd's The Dark Side of the Moon.
123B — A Tattler's Tale
In one scene, Lucy can be seen reading a book with various strange symbols. Between the scribbles the words Klaatu Barada Nikto can be spotted.
124a — Funny Business
Luan's wall has a stick-figure version of Ctrl+Alt+Del's infamous "Loss" comic on it.
When the batteries to the walkie-talkie runs out, Lincoln reacts "Dang it, the walkie's dead."
126b — Homespun
The werewolf book that Lucy debates on reading is titled "Hungry Like A..."
The sheet that Lincoln uses for the lining of a covered wagon has a logo for Starship Groupers.
During the "bad TV reception" flashback the television flashes The Dream Boat and something that looks exactly like Peanuts.
After Leni's leaky walls remembrance, it's mentioned that it happened because someone flushed the toilet in the upstairs bathroom. Luan's reaction is to comment "Urine Trouble there!"
Season 2:
201 — 11 Louds a Leapin'
The title itself is a reference to "The Twelve Days Of Christmas", more specifically, a combination of the lines "Ten lords a leaping," and "Eleven Pipers Piping".
Rita wonders when was the last time she and her husband had two full days for themselves. Lynn Sr. replies that it was in the "Summer of '98", mentioning Bill Clinton, Spice Girls and baseball player Mark McGwire.
When the Loud pets attempt to break Watterson out of the pet sanctuary, the "Paris" theme from "Thieves in Time" can be heard in the background.
The pound the pets get to capture the new pup is called Green Mile Pet Sanctuary. The Green Mile is slang for a condemned inmate's last walk before they are executed.
The last puppy shown in the Green Mile Pet Sanctuary is a dead ringer for Snoopy.
211b — Pulp Friction
The title is an obvious shoutout to Pulp Fiction, in fact during the the Episode Title Card, a slightly altered rendition of Misirlou plays.
At the beginning of the scene in which Lucy opens her haunted corn maze, a Freeze-Frame Bonus will reveal a kid dressed as a Captain Ersatz of Harry Potter on the right corner of the screen. He appears again at the end of the episode.
225b — The Crying Dame
The title is a direct reference to The Crying Game, an R Rated film about a transgender person facing prejudice. It's also about terrorism. And rather violent.
The title card shows Lincoln and Clyde standing on a platform, reminiscent of a level from Super Mario Bros., with Lincoln and Clyde dressed as Mario and Luigi, while an 8bit song plays in the background. The title also alludes to Nintendo's hand-held device, the "Game Boy."
The plot and title are based on Silence of the Lambs, complete with Luan donning Hannibal Lecter's iconic getup.
519a — Dad Reputation
The title is based on the Joan Jett song "Bad Reputation".
519b — Dream a Lily Dream
The title is derived from the song "Dream a Little Dream of Me".
The plot is an homage to the film Inception, as is the plot point that the visitors can be trapped in the dream if the dreamer wakes up.
The BFS Lily wields in the climax resembles the Buster Sword.
Season 6
601a — Present Danger
The in-universe David Steele franchise is revealed to be a pastiche of James Bond. The title character himself is based on 007, he's got an Expy of Q in the form of Cue Ball, and his rogues gallery copies various Bond villains.
Continuing the Bond reference, Lincoln's introduction as David Steele parodies the iconic Bond opening. At the end, Lynn Sr. and Leonard join in on the act.
The episode's villain, Rusty, behaves like Bond's archnemesis Blofeld, even having a Right-Hand Cat.
601b — Stressed for the Part
Mrs. Bernardo tells Leni that she was once involved in a lauded production of Kats, adding that it's spelled with a "K" for legal reasons.
603b — Haunted House Call
The Dollars Cheryl paid the Mortician club with have Scrooge McDuck on them.
604 — Save Royal Woods!
The song "Keep Us Around" is a rap number about colonial Royal Woods, not unlike Hamilton.
from Command & Conquer: Generals are heard.