Anti-Hero: Calling him "heroic" is a massive stretch, given that all his actions are driven by pettiness and/or bizarre emotional impulses. He gets more heroic in the third movie, though.
With iCarly in Fred on iCarly and the iCarly episode iMeet Fred—Fred is fictional in the iCarly universe, but iMeet Fred features two exclusive Fred videos, both featuring iCarly characters (the second of these videos can be seen here).
Dark Horse Victory: Fred and his mortal enemy Kevin compete for class president. The winner is a girl called Cleopatra who Fred claims "didn't have any ideas" and was just sort of there.
Darker and Edgier: Averted, the show is brighter than the web video.
In the web video, it is implied that Fred's mom is a prostitute.
Dawson Casting: Self-inflicted—Lucas Cruikshank was 14 when he created 6-year-old Fred.
Averted in the movies with Fred, as Lucas was 16 when filiming took place and Fred was depicted as a 15 year old there. However, it's played straight with the ages of Jennette McCurdy (17), Jake Weary (19) and Pixie Lott (18) during filiming. Fred is the only person in the middle school he goes to that actually looks like he could reasonably be a middle schooler.
Possibly inverted with John Cena as Fred's imaginary dad, unless he was around 18 when Fred was conceived (and that's only if Fred's dad is the same age as Cena, any younger then...)
DVD Commentary: The first movie has one by director Clay Weiner, writer David Goodman, and actor Lucas Cruikshank.
Even Evil Has Standards: Kevin one time pretended to be Judy, saying that he and Judy had broken up, and wanted to date Fred. When Judy found out she stated that was too far, though Fred thought Judy was only acting.
Flanderization: Inverted with The Movies, and for good reason: an entire two-hour movie where Fred talked in an incredibly annoying high-pitched, fast-paced voice would get old REAL fast. (He's still pitch-shifted, but not as much.)
Mood Swinger: In the first movie Fred throws up on Judy at her party and she tells him to leave, but then she runs after him seconds later.
The Movie: Three of 'em, both of which were intended for theaters but ended up premiering on Nickelodeon. (The first film did make it to theaters in the UK due to the distributor capitalizing on Pixie Lott's popularity over there, but it bombed spectacularly.) Nickelodeon has also picked up a TV series (Fred: The Show) and then a third movie (Fred 3: Camp Fred).
Not Even Bothering with the Accent: In the first movie, Pixie Lott's character Judy is explicitly stated to be Southern. However, you wouldn't know it since Pixie speaks (and sings) with her natural British accent throughout the whole film.
I'm fairly sure that Fred was the one who claimed that Judy was Southern, and... well, we know how Fred is. Fairly sure it was completely deliberate.
Overly Long Gag: In the first movie, when Fred's faced with a car repairman who doesn't speak English, he thinks he is being messed with and proceeds to run away screaming, while we are shown brief shots of different areas (like near a fence, on a railroad track and even on a rollercoaster track). This continues until he runs into a live dam.
Parental Abandonment: His mom loves bars and staying out late and is almost never there, and his "rock star" dad is on Death Row. The first movie implies that Fred's dad actually lived nearby (until the movie's events actually occur), and was never in jail (or a rock star), but FRED makes a Diorama has Fred's dad appear in jail.
Pet the Dog: The end of the first movie—Fred's wacky scheme for instant popularity doesn't work, but Judy turns up at his house to sing with him. Maybe.
Playing A Tree: Fred gets cast as a tree in the school production of Grease. And he loves it.
Time Skip: Implied in the first movie (and, by extension, the second)—it's stated that Fred's 15 (and his voice isn't as high), whereas the YouTube videos state that he's 6.
Tuckerization: The movies reveal that Kevin's family's last name is Libo, the same as writer David Goodman's cousins (as mentioned in the first movie's DVD Commentary).
Undercrank: How Fred gets his high voice and fast movement.
Unreliable Narrator: Even more so in the movies, where half of the events don't even happen.
Unnamed Parent: Both of Fred's parents were this, but their names were eventually revealed:
Villainous Breakdown: Kevin at the end of the third film after Fred and his camp's song turns out to be surprisingly good and his plan b fails completely. When Fred actually wins, Kevin loses it.