Basically this is Costume Porn applied to a cape (or robe worn like a cape), where that piece of clothing is expensively decorated. This was common throughout history, for both men and women, as capes of various kinds were a common clothing item, and clearly visible due to their size. Thus a grand cape would easily be a way to show off one's wealth and social status. In fiction, it's a way to either show the same for a high class character, and/or for the artist/costume designer to show off.
Now how decorated a cape can be will vary. It can be trimming just part of the cape, to lining it, to entirely covering it. What is decorating the cape can also vary. Realistic capes can be decorated with Fur, embroidery, gold lame, and even expensive dyes can count. Fantastic capes can decorate them even more, from armor, to fire, to Tron Lines.
You might think pimping out a cape would be easy, but capes are a lot of material to work with, and even just edging one will take several yards of trimming. And of course historically all the decoration was done by hand. Thus anytime you see a cape where there is some kind of fancy trimming, lining, decoration, or other kind of work done, it counts as this trope.
If this cape is worn for protection, it overlaps with Stylish Protection Gear. If royalty or nobility wears one, it usually is part of their Requisite Royal Regalia (and why the trope Ermine Cape Effect is named so).
Now let's make it clear that the cape itself has to be decorated. So even though Superheroes Wear Capes, the majority of their capes will not count as this trope (even for the villains), as those capes are usually simple, no matter how cool or flowing they may be.
- Batman's cape counts in the continuities where it has a mechanism built in that turns it into Cape Wings.
- Ordinarily, Wonder Woman does not wear a cape. For her, capes are more like what they are for most people — an unusual sort of formal wear. So when she does wear a cape, it tends to be a lot more pimped-out than your traditional superhero cape.
- Captain Marvel of Shazam has a cape with gold edging. Though unlike other superheroes who can sweep the floor with their capes, Captain Marvel tends to favor a shorter, waist length matador style cape that looks great slung over a shoulder. Though it Depends On The Artist, really. Captain Marvel's cape has also been a regular cape and even a bizarre "Hoodie Cape," as seen in modern comics.
- Doctor Strange has a particularly magnificent cape, made out of bright red material with fancy golden trim that merges seamlessly with a matching golden mantle, topped with the kind of gravity-defying collar that makes cosplayers weep. Fortunately it's also useful — it's his Cloak of Levitation and enables him to fly.
- The traditional costume of the Green Lantern Alan Scott includes a purple and green opera cape with an especially impressive collar. Somehow he pulls the look off.
- Wonder Woman and the Star Riders: Wondy's cape is Gem-Encrusted and Purrsia's is edged and lined in purple leopard spotted fur.
- Belle's winter cape in Beauty and the Beast.
- In The Care Bears: Adventure in Wonderland, both the queen and princess of Wonderland wore ermine-trimmed capes, but the queen wore one that was trimmed with red hearts.
- Megamind, with much fanfare, dons a cape for battle with gargantuan spikes on wide shoulder pads and the high collar to end all high collars called "The Black Mambaaaaaaaaaaa..."
- At the end of Barbie in a Christmas Carol, Eden wears a short, hooded cape trimmed with white fur over her Happy Holidays Dress.
- In Frozen, Elsa and Anna each get two capes. Elsa has her purple coronation cape and the snowflake themed cape attached to her ice dress. Anna has a green cape she wore to go searching for her sister, and later a warmer pink cape.
- Frozen II give the sisters two more capes. Elsa's adventuring and "spirit" dress come with a two piece capelet that looks like a pair of wings. Anna, meanwhile, gets a purple warmer cape as part of her adventuring outfit and later wears a flowing green coronation cape with purple inner lining as part of her Queenly raiment.
- Florence Welch of Florence + the Machine, while singing "Shake It Out" on The X Factor, wore a dress with six white capes held in place. Also, on her Ceremonials Tour, she wore a black cape with an elaborately patterned inside.
- Ace Frehley of KISS had a pimped-out cape to go with the pimped-out epaulets of his Space Ace costume during the Dynasty and Unmasked tours.
- Gorgeous George was the first wrestler to use the pimped-out robe variation. Ric Flair is a more recent example.
- "Nature Boy" Buddy Rogers was known for wearing this to the ring.
- Mil Mascaras usually wears capes with rhinestones and designs to match his current mask.
- Randy Savage used to wear them in the 80's in the WWF.
- Stage Magician Zark in Cirque du Soleil's Zarkana wears a cape patterned with an image of giant rose petals. His Nice Hat is printed over red rose blossoms to match.
- Sera Myu: Mamoru goes from Ominous Opera Cape / Badass Cape to a blingtastic lavender one with his future self, King Endymion.
- The titular character of The Phantom of the Opera wears one, decorated with sequins.
- The Count and Viscount von Krolock of Tanz Der Vampire both wear one. Herbert only wears his for his introduction scene and the Midnight Ball, but the Count is never seen without his cape.
- Some Dungeons & Dragons magic items are capes that require them to be pimped out to work, such as the ermine lined "Cloak of Lordliness", which is sewn together with silver thread.
- Warhammer 40,000: Many of the Primarchs have fancy capes, much like their father The Emperor of Mankind who has the fanciest one of them all.
- Hades's cape in Kid Icarus: Uprising: Just look!◊
- The generals in Dragon Force wear capes that are not only fancy, but float just above their shoulders.
- Rosa's outfit in the remake of Final Fantasy IV is actually two capes, a lace one worn over the regular one.
- The leaders of the Three Kingdoms in Dynasty Warriors 7 all have ridiculously ornate capes, each one etched with a design representing their kingdom in extreme detail; Liu Bei with a dragon, Cao Cao with a phoenix, and Sun Jian with a tiger.
- Merlina's embroidered robe in Sonic and the Black Knight.
- Jessica Alkirk of Lunar: The Silver Star. See here◊.
- Skillcapes in Runescape have large, ornate shoulderpads, and lots of trimmings. The Dungeoneering Mastery Cape even includes a magical smoke generator that makes smoke trail behind you when you walk.
- Taken Up to Eleven with the Max/Completionist capes. They are fully pimped out, trimmed to the max capes with aforementioned smoke generators, and they are even color customizable for max pimping. Of course, the requirements to get one are quite extensive. (The max cape requiring you to reach the max level in all skills, Trimmed Completionist is well, 100% Completion)
- King Ladekahn, Queen Corellia, and Lady Melodia of Baten Kaitos.
- Touhou: Utsuho's cape is decorated with an independently scrolling star field.
- Likewise, in Hopeless Masquerade, Miko dons a cape that changes colors depending on her popularity level and also features an Unmoving Plaid.
- Ghetsis' cape in Pokémon Black and White is pretty pimped-out.
- Tyto the Swift from Gigantic wears a cape that's made to look like a bird's wing. It's said to be a gift from hawk-spirits who wove it from their own feathers.
- In The Elder Scrolls background lore, the Imga, a race of intelligent "ape men" native to Valenwood, wear these in an attempt to ape the Altmer (High Elves), who the Imga idolize. One corner of the capes is perfumed, which they hold over their noses when humans are around. (The Altmer have a strong cultural dislike of the races of Men, so the Imga pretend to find their smell offensive.)
- Bound Adventures: A fur-trimmed cape is the most common luxury among the Blue Blood and Royal Blood, even when they are wearing bdsm gear, or little else. Even Livia can't resist taking one for herself when she's helping Irina again escape from the Duchess's castle.
- Pandora frequently wears one with a fur collar in El Goonish Shive.
- In Knights of Buena Vista, a Campaign Comic covering Frozen, it turns out Elsa's coronation cape was supposed to be even more pimped out, but she sold the ermine, meant for lining the cape, for fourteen gold a pelt.
- The Emperor in Memorabilia has a long, flowing cloak complete with fluffy fur trim.
- Many coronations have these. The capes are usually decorated with gold, ermine, or both (see the coronation pictures of Elizabeth I and Russian Tsars).
- In the 1930s, to about The '50s, at least in the US, short shoulder cape of white ermine was a popular garment for young society women 18. Thus movies around the time used it as a way to identify these characters as such.
- Liberace was famous for his flamboyant capes (no pun intended).
- Polish Husaria wore a leopard skin as a cape. That is automatically awesome, all the moreso when it was worn over the more typically impressive red and gold cloak and steel-and-gold armour.
- Alternative Rock singer Stevie Nicks in her band Fleetwood Mac loves to wear long flowing capes with decorated jewels and pearls and flowing shawls and ponchos with rubies and rhinestones to look more badass. She always does.