Sparkles everywhere! Must be Magic!
For the longest time, humanity has an historical fascination with shinies. That might have to do with how some of the more precious materials tend to sparkle, but in the end, there is just something in how stuff shines or sparkles that leaves people staring on with, well, shiny eyes. That goes double when the effect is of a mysterious nature.
Because of this universal fascination, the trope's simple logic is that if you want to indicate visually how valuable, magical, or just special anything is, then put a lot of shiny sparkles, or anything that makes sparkles (like glitter or small crystals) around it.
Even when the sparkles are justified for the inherent qualities of the materials used, it's still a bit exaggerated in fiction.
Fairies are often prone to sparkling. And this is often associated with Fairy Tales and Princess Classic.
Many video games use sparkles as a form of Notice This.
Definitely on the shiny end of the Sliding Scale of Shiny Versus Gritty.
A Super Trope to Bishie Sparkle, Sparkling Stream of Tears.
Compare Everything's Sparkly with Jewelry, Gold Makes Everything Shiny.
In The Wallflower and its anime adaptation Yamato Nadeshiko Shichi Henge (Perfect Girl Evolution), all the pretty people are represented with sparkles, which is referenced by Gorn-loving protagonist Sunako; the people that do this are known as "people of light" (Sunako is one of the "people of darkness", of course).
In one episode of Gankutsuou, Haydee attends an opera wearing what can only be described as the sparkliest dress ever.
Pokémon Contests feature these in spades, especially in Sinnoh. And we mean literally; there are plenty of spore-based attacks that resemble sparkles.
Starting from Diamond and Pearl, Pokémon now sparkle when released from their Poké Balls, which means that, as of 2006, every single episode invokes this trope!
Karakuridouji Ultimo. They had to have spilt glitter glue on the pages. Ultimo with all his Bishie Sparkle scenes. (Yamato gets in on it too.) the bonus comic Ultimo Ulate had entire pages with nothing but sparkles for backdrop. There was even a sparkly rainbow on one page. Oh did we mention the food yet?
By the way, this is a science fiction, mecha/robot, shonen series.
Soushi Miketsukami does that often when talking to or about Ririchiyo Shirakiin in Inu X Boku SS.
Dreamgirls: Jimmy "Thunder" Early claims he invented flashy costumes, four cannons of confetti go off in the finale, and the credits look like they're set in a starfield.
The 1984 movie Legend (with a very young Tom Cruise) is FULL of sparkles. Each of the characters is covered in glitter (including the devil-esque character's hooves). As are many of the sets, especially after the planet flash-freezes. The treasure trove scene where Tom Cruise gets his golden sword and shield takes it especially far over the top.
In The Wizard Of Speed And Time, the television special's producers argue over whether the use of sparkle F/X will exceed the program's budget. They eventually agree to use one sparkle. Meanwhile, Mike (The titular Wizard) animates a plethora of sparkles for his own scene for almost no cost.
Twilight's vampires sparkle in direct sunlight (you'd usually think vampires burn, but that's Common Knowledge from Hollywood films).
In the Discworld novels, the Glingleglingleglingle Fairy has the job of heralding major fairy magic by ringing a handbell and throwing some chopped tinsel in the air. Discworld magic usually happens without any fuss, but fairies know what's expected of them.
In one scene near the end of the Discworld novel Hogfather, when Susan (Death's grand-daughter) hurls the nursery room poker (made of rather cheap metal) through Death's ribcage at the assassin Mr. Teatime behind him, where it embeds itself in Teatime's chest and kills him, the flying poker "made a ripping noise as it shot through the air, and trailed sparks". Death later admits to Susan that he did add the sparkly stars and the noise, because he thought it would be appropriate (because there were two small children watching).
There was an Anti-Role Model type TV ad for heroin, with a sparkly logo, a song beginning "Everybody's doin' it, doin' it, doin' it," and black-and-white footage of a guy throwing up in a toilet.
The transporters and replicators in Star Trek do this.
On The Daily Show, magic is usually indicated with a bit of hand-waving and the word "Magic!" The reason they don't use sparkles becomes clear when they briefly experiment with them - either the desk gets covered in glitter which someone will have to clean up, or Special Effects FailureEnsues.
The old (1998-2005) set was pretty sparkly itself. I'm thinking particularly of that glittery splash of magenta on the backdrop behind Jon's head.
Almost every Ke$ha song has at least one reference to glitter in it.
The Japanese music video "LOVE Dokkyun" by Club Prince is a comically notable abuser: random sparkles cheaply overlayed throughout a large portion of the video, intersecting with Bishie Sparkle. The sparkles eventually digress into pink spinning hearts.
While we're on the subject of Japanese music, Morning Musume's video for "One Two Three" looks like it was wrung through a Blingee filter several times.
Simple Minds did this a lot starting with their "Sons and Fascination" album, mainly do to the keyboard style of Mick Mac Neil. After he left, they decreased in their "sparklyness".
Fandom Wank denizens parodies this by using sparkly text to mocking out stupid or self-evident statements, calling it "The Sparklies of Truth" . The trend (and the nickname) began after reviewing a wank where the main person involved expressed her thoughts by using bold text with a sparkle background in a failed attempt to impose her point of view, which was as batshit insane as you'd expect from anyone who uses sparkle text for emphasis, boiling down to "fan fiction is evil but child abuse is just fine!"
The NORAD Santa Tracker shows Santa's current location as an icon of Santa surrounded by sparkles.
"The Firefly Boy" in Cirque Du Soleil's Kŕ is a guy who swings from a trapeze and is covered in sparkles.
27.84% of every Cirque show is glitter.
In Mark Siano's Modern Luv, Mark and his chorus dancers don Sparkletards for several numbers, and in the 2012 run, Mark wore a green Sparkletard in the second act for St. Patrick's Day.
The majority of Zelda's attacks in the Super Smash Bros. games involve sparkles. The fairies in the Zelda games sparkle too, so much that you can't actually see their bodies.
Shiny (or Alternate Colored) Pokémon sparkle upon leaving their Poké Balls (or being randomly encountered in the case of wild Pokémon). It used to be so that you could tell they were special even if you were playing on a monochrome Game Boy, but the effect became so characteristic of Shinies that it's appeared in all games since.
The Sims 2 features sparkles as often as it can get away with: in age transitions, during WooHoo, in Pets, kittens and puppies are born in a puff of sparkles, food made with fresh ingredients in Seasons sparkles and refills a lot more hunger more quickly, and in Apartment Life, witches sparkle in colors appropriate to their Character Alignment.
The Sims 3 ditches the WooHoo sparkles, but adds sparkles for the mundane act of building walls. In the World Adventures expansion pack, a Lifetime Reward called "Eye Candy" gives pink sparkles to your sim (and a positive moodlet to any other Sim who speaks with the sparkly one).
In Persona 4, Teddie eventually grows a human form. It always sparkles; and he is very bishonen. His ham-handed attempts at "scoring chicks" prevents him from taking advantage of it fully; although it probably does prevent women from beating him up for trying.
In World of Warcraft most healing spells DO sparkle, making whoever is being healed better, well, medically better.
An update for the PlayStation 3 added a new home background theme, naming it "Original" and setting it as the default, while renaming the old one "Classic." The difference? "Original" has sparkles!
Used in Glider PRO for a Notice This effect... or whenever else the level designer feels like making something sparkle.
Same with the Resident Evil games. Any important item will sparkle like a little star. Lesser items in later games will have a white gleam running over them.
In Team Fortress 2, you can see players sparkle in Pyro Vision when in reality they are on fire.
There is also a Sparkle particle effect for community and self-made versions of weapons.
The webcomic Strange Candy has one Adventure Town based on this principle. It's full of Amazons that use sparkles as a weapon to weaken the will of the enemy. The climax comes when Petra uses her mastery of weapons (she loves to use Hyperspace Mallets) to "hammersparkle". In other words, she "suffocated" the enemy by sparkling so much that even the sparkle-loving Amazon couldn't handle the overload.
Defied in the Anti-Cliché and Mary-Sue Elimination Society. Since Chrys's foundations are in weeaboo-ism, she likes to emit "desu" sparkles (which are not to be associated with the Japanese verb of "to be"). This is a problem as people can be physically or mentally harmed at the sight of sparkles (they drive Tyler crazy and shock Karissa into a daze). On the other hand, they can be useful in defusing an angsty atmosphere or can be used like ninja stars. Yes, you heard me.
Excessively colorful and over-decorated canine characters are often referred to as "Sparkledogs".
The sparkles in the Shrek movies were nicknamed "Disney Dust" by the animators.
Jem. Many of the terrifyingly fashionable clothes the band wears have sparkles...and then there's the videos. SPARKLE VIDEOS.
One of Jem's most famous shots is from a video that depicts two people kissing — and a giant sparkle right where their lips meet, which makes no sense, as kisses generally don't sparkle. Neither do eyelids, but Jem's were prone to do so when she winked (see the third-season DVD cover for an example of this one).
PJ Sparkles is overflowing with sparkles. The title even tells us so.
Winx Club has each of the girls' fairy wardrobe sprinkled in sparkles. Some of the girls have even worn sparkly wardrobe once...or twice...or more.
Twilight Sparkle, anyone? In the show, magic is indicated by sparkly halos, so it's not surprising that the pony with "Sparkle" in her name represents the Element of Magic.
In the first episode, Rarity is introduced decorating Town Hall, and swaps out a plain ribbon for a sparkly one. The way she expresses her satisfaction with the choice can also be seen as Foreshadowing about Twilight's magic abilities (which to that point had only been shown to handle books):
Rarity: "Sparkle always does the trick, does it not?"