Actor Allusion: In the theme song Tom is briefly shown wearing a shirt with an asdfmovie character, in the Halloween Special he reads a magazine called Ska. His VA uses Tom Ska as Youtube and Twitter nickname.
The director of the movie in Spares is called Christopher Bingbong (as seen during the movie's end credits). He was voiced by Chris "Bing" Bingham.
Author Appeal: There are at least six films dealing with zombie apocalypses (Apocali?).
Anachronism Stew: For some reason, the British Army uses Kalashnikovs and American helicopters, as seen in Moving Targets.
Art Evolution: Their earlier videos were very blocky, but as time went on, they developed a better art style.
Art Shift: Paul's style is less sketchy than Edd's, and it's noticeable. He's been drawing like this as early as 2007, if you check out Paul's Jasper Green character.
Tom's Tales of Crazy is animated by Pearl Zhang, in a style closer to the late Edd's.
Author Avatar: All the main characters are named after, voiced by and vaguely based off the creator and his friends.
With Edd Gould's passing, the voice of his character is now Tim Hautekiet. The rest of the cast remains the same, though.
Ascended Fanboy: Super Smash 3 DS, real name Mark Lovallo, was the artist and occasional writer of a fan comic based on the show called Eddsworld Guest Comics. Come 2013, he's writing, directing, animating and overall creating the Eddsworld Movie.
Edd smashes Tom's bass in one episode. It's referenced two times in future episodes that release a good deal later.
In the first Zanta Claws episode Edd says he thought the real Santa died years ago, only to meet what is apparently Santa at the end. In Zanta Claws 3 Zanta offhandedly reveals he was the original Santa when he was alive.
Butt Monkey: Tom and Matt end up on the receiving end of a lot of abuse in the cartoons, although Matt may arguably get it worse because it's obvious Edd and Tom don't like him.
Call Back: In "Space Face Part 2," Tom is seen wielding Future Edd's weapon from WTFuture.
When Matt is taking his... thing to his room in Hammer and Fail, he is heard muttering "It was better being ruler of everything, it was awesome."
Tom: Have you ever noticed how we hardly ever swear?
Edd: That's because it always [censored] comes up as these [censored] blocks.
Tom: Well that's just [censored] stupid! Whose [censored] idea was that?
Edd: Probably the same [censored] [censored] who thought it would be a good [censored] idea to [censored] [censored] [censored] and give you [censored] [censored] [censored] instead of [censored] [censored] [censored] and stuff.
Eyeless Face: Instead of eyes, Tom only has two black holes in his face (although he can still see... somehow). His mother was a bowling ball and his father was a pineapple, explaining his lack of eyes (and round head shape).
Lotus-Eater Machine: Subverted in Zanta Claws II, where Zanta gives the protagonists "their hearts' desires" (for Tom, a pair of eyes, for Matt, a heap of money, and for Edd a swiming pool filled with Coca Cola). All these gifts were physically real, and the painful side effects (It Burns!) were due largely to the trio's own stupidity.
Missing Steps Plan: In "Zombeh Nation" Edd's plan to dominate the world using bacon has: step 1: bacon, step 2: bacon with an arrow pointing to the world, step 3: ????, and step 4: world domination.
Monumental Damage: Defied. The demon possessing Matt's body wanted to but Matt likes monuments and refuses to go along.
No Ontological Inertia: In Climate Change, when the gang disconnects everything, not only does the tsunami stop BUT it goes backwards restoring all the destroyed buildings.
The Nth Doctor: The in-universe explanation for Edd's Voice Change is his being zapped by a voice-changing raygun in Space Face Part 2.
Oh Crap: Edd has a facial version when, in "WTFuture", he hears the guy from outside the diner say "Hey, Edd". While Edd is still in his booth.
Paper-Thin Disguise: When Edd, Tom and Matt tried to disguise themselves as fish in 25 feet under the seat. It actually worked for a time.
An even more extreme example is when Zanta Claws tries to disguise himself as normal Santa by just switching hats. It was enough to fool Tom.
Posthumous Collaboration: Edd apparently didn't want the series to end after his death. His friends now carry on his work with a new animator and a new voice actor for Edd's character.
The former is averted since Edd's death - Ridgewell stated on Twitter that he wants to avoid being sued for copyright infrigement, so coke became cola.
Parodied in "Ruined"
Tom: What in the name of this delicious bowl of Eddsworld Cereal happened to my bass!
Puff of Logic: In Zanta Claws II, Edd, Tom, and Matt fly by car to the North Pole by way of the Zed Gear. Matt questions how a car can fly, and their flight is cut short.
Pun: Edd frequently makes these, especially in the comic:
Edd: I can't beLEAF Matt got stuck in this tree! He was only trying to reTREEve our kite!
Tom: This is no time to make ACORNy joke!
Edd: Well, I'm STUMPed.
Matt: Uh, guys, I'm still stuck?
Put on a Bus: Tord was part of their adventures, up until "25 ft. Under The Seat", where he left. When he found out that Edd died, he decided to make a video giving his reasons for leaving. Unfortunately, Tord deleted his Youtube account. For short explanation, see Fan Dumb on YMMV page.
Edd, Tom, Matt and their future counterparts in WTFuture.
Edd and Larry in Spares.
Tom's Tales are fully voiced by Tom Ridgewell.
Tempting Fate: Most of the bystanders in WTFuture are killed off or maimed this way. The man who demanded extra crispy chicken gets his hand scorched to the bone via the laser (which also scorches the chicken), a man pushes past an old lady rudely (and is promptly vaporized,) and Superguy and the man with him are vaporized because Superguy is immune to "Everything in the world, except giant lasers."
Also, in Moviemakers:
Tom: Even if they don't [like our film], it's not the end of the world. (cut to destroyed London)
That Poor Car: In Hammer & Fail Part 2, Tom gets flung backwards into his car, setting off the alarm until he turns it off.
When he was around, Tord was pretty bad, maybe even worse. For example, in "Zanta Claws I," Edd got yelled at for ignoring his milkman's Christmas Card (mild apathy), Matt got yelled at for stepping on a bug, and Tom got yelled at for eating a pie that he wasn't supposed to eat. Tord got yelled at for playing paintball with real guns. (He seems quite proud of himself when reminded of this incident.)
Trigger Happy: Tord. He brings guns in almost every episode he was in.
Vehicle Vanish: Played with in Zanta Claws. Zanta is about to attack the four, until an entourage of Coca-Cola vans blasts by. When they clear, only Matt is left. After an awkward "Oh... um..." a smaller entourage comes along and he too vanishes.
Played with again in WTFuture where upon looking down an alleyway containing Future Edd, a truck comes along and he vanishes, only to appear next to the trio seconds later. It's also used as a sound effect censor in the same scene.
Visual Pun: A lot of the early comics consist of these.
Weaksauce Weakness: Edd is saved from death by accidentally discovering the Grim Reapers' one weakness: Gravy.
Wham Line: "Hey Eddheads. We have some bad news..."
Zombie Apocalypse: 5 videos, 4 of them are connected, but the last one, Fun Dead, is completely unconnected to the "Zombeh Attack" series.