Parodied in FoxTrot at the end of a 1997 storyline where Paige receives an evaluation copy of the upcoming sequel to Jason's favorite computer game:
Jason: What's that? Paige: It's a letter from the President of Blizzerbund Software. Jason: No way! What's it say? What's it say? Paige:(reading letter) "Dear Ms. Fox, thank you for your evaluation of our Riviablo CD-ROM beta. Per your suggestions, the final version of the game will have less violence, cuter monsters, and significantly easier puzzles. P.S. Thanks especially for the great idea to change the game's title to Happy Town." (A few seconds later) Peter: I thought they sent you a form letter. Paige: Oops. You're right. I must've misread it. Andy:(offscreen) Jason, will you stop bawling long enough to tell me what's wrong?!
Also, a later storyline has Andy forcing Peter and Jason to play Mothers Against Gory Games-approved versions of popular video games (such as Nice City) in an attempt to make them stop playing video games altogether.
Sir Orfeo, a Medieval poem by an unknown author (and translated by J. R. R. Tolkien) is a much, much lighter retelling/reimagining of the story of Orpheus. His wife is simply kidnapped by The Fair Folk rather than dying, and, unlike in the source material, our hero is successful in rescuing her and bringing her back home. It's arguably the UR Example of a Fix Fic.
LEGO's Hero Factory, when compared to its predecessor BIONICLE. Bionicle had plenty of Nightmare Fuel and some death, while Hero Factory has a more comedic feel to it and is made to appeal to little kids. This is one of the main reasons fans have bashed at it.
The SCP Foundation has a list of Anomalous Items, Events and Locations that are too boring or harmless to have SCP status, with many of the events never repeating again or the items getting incinerated. It's also filled with way more snarky quips from the Foundation personnel than a standard SCP log.
Neopets was made by, and for college kids when it first started. The early plots all were filled with black comedy, where the staff members (fictionally) were killed off one by one (the players got to vote on who died). The site was made kid friendly after two years, but the old pages from early plots still exist, which are all Nightmare Fuel.
This trope is parodied in Saturday Morning Watchmen, with an attempt to make Watchmen lighter and softer. It's a parody of the animated cartoon versions of films geared towards adult audiences. In particular, Rorschach describes himself as "nutty" (he's relegated to comic relief) and the Comedian... has a crush on Silk Spectre.
After the Incarnates arc in We Are Our Avatars, which is chockfull of Grimdark, many of the Arcs started to get lighter, although many exceptions have applied.
Tobuscus started out his vlogging career with a very gritty, profanity-laced style, clearly going for a "bad boy" vibe. Around 2010, however, his popularity started to really grow, his sponsorships took off, and his teenage niece, Ciara, started appearing in his videos — and suddenly the grittiness was gone, replaced by a Toby who never swears, pretends to be oblivious to things like sex and alcohol, and is almost entirely comedic. His niece aside, this was almost certainly a calculated career move to broaden his appeal, although there are still occasional comments on his videos expressing longing for the "old Toby".
While still retaining the serious tone and a lot of the dark aspects of DC Comics, DC: United We Stand aims to be this. For example, a lot of the darker events (such as Identity Crisis and War Games) have been retconned in some way, big or small, to achieve this.
Many YouTube Poop authors who indulge in Vulgar Humor will do at least one clean poop. For example, cs188 has "Ballmer Sells Clean Windows" and "The Apocalypse Bulb", and ChickenPika has "Rosen of the Valley of the Windmills". Relatedly, poopers who generally keep their material family-friendly, such as DaThings1, can be seen as this to the YTP genre as a whole.
The RWBY spinoff RWBY Chibi is this to the original RWBY. While the latter half of Volume 3 was a series of Wham Episodes that steered the show well into Darker and Edgier territory, Chibi seems to emphasize the more light-hearted comedy and slice-of-life aspects of the show's early episodes.
The Twitter parody account @ff7_blazed goes out of its way to avoid the original game's horror themes and violence. This even goes for small moments that no-one would have noticed if the parody had just skipped completely - for instance, at a point where the original game had Cloud punch Aeris while under the influence of Sephiroth's mind control, the parody has Aeris thank Cloud for not punching her. Most fights are resolved by having Cloud talk his way out of fighting people by declaring himself a pacifist or making friends with them - Sephiroth's murder of Aeris is resolved by giving him weed, and she survives. The parody contains a lot more drugs than the original, but even so the stoner heroes will stop every now and again to deliver An Aesop about how they don't do 'real' drugs, and the characters associated with drugs that aren't weed are invariably villains. (The one exception is Cloud's use of DMT to defeat Sephiroth).
The My Little Pony: Friendship Is Magic series Scootertrix the Abridged is this to the manyother MLP Abridged Series out there, that get a lot of humor out of reinterpreting the mane six as sociopaths, and/or turning Equestria into a technicolor evil empire. Here, the mane six are flawed but still clearly trying to do the right thing, and Equestria is beset by external dangers but still worth defending.
DC Super Hero Girls combines this with Younger and Hipper to create a web series featuring younger incarnations of the classic and more recent superheroines and villainesses. Poison Ivy, especially.
Major League Baseball opened the 1998 season with two new teams, both named after incredibly deadly animals - the Arizona Diamondbacks and the Tampa Bay Devil Rays. While the Diamondbacks are much less threatening than their name implies, the Devil Rays changed their name to the Rays in 2007, the name now describing rays of sunshine rather than dangerous marine life. Oddly, ever since then they've been extremely good. It was also changed due to Moral Guardians (and reportedly former Ray Josh Hamilton, who became a born-again Christian after kicking drug addiction) thinking that the name promoted Satanism.
Aerogel, if you want to take this trope literally. It's the lightest known solid and has the consistency of styrofoam.
Some grandparents are accused of this by their children.
A lot of people will describe college like this to high-school students, especially those who didn't care for high school and are afraid college will be more of the same. They mention that while the work will be more difficult, the environment will be a lot more pleasant, since everybody is there by choice, and there's a lot less bullying and teasing going on.