Princess Fillet of Brave Fencer Musashi wears a white dress with a pleated underskirt, an overskirt edged with alternating chevrons of white and red, a large red bow on her collar and hair, little red bows holding her bodice together like buttons, undersleeves that are like scarves, and a belt.
Princess Karen in Brave Soul wears a pink dress with gold trimming, ruffled cuffs and collar, and a green jewel at the front of the neck.
In Castlevania: Lament of Innocence, Sara wears a white dress with a blue and white bodice that has ribbons wrapping around the sleeves, brocade trimming the bodice, and a strip of embroidery down the front of the skirt. Elizabeth wears a dress of white and brocaded gold, hanging sleeves with tassels on the tip, and a light gold sash and cape.
The Guardia royal dress in Chrono Trigger is a (mostly) white dress with puff sleeves, a puffy skirt with two layers of overskirt, High-Class Gloves, and ruffles edging most of it. Queen Zeal wears a gold dress with purple trimming. Schala's relatively simple dress has hanging sleeves and a white-trimmed collar.
Dark Souls has at least a couple. Princess Gwynevere wears a white and gold dress with lace trimming, hanging sleeves, and a strip of fabric wrapped around her legs like a skirt. Dusk of Oolacile wears a light golden dress with pearls, a petticoat, puff sleeves, lace gloves, and a laces shoulder cape.
Princess Rozalin's dress in Disgaea 2: Cursed Memories just might be the most extravagant out in the Disgaea series, which is a series not hurting for fancy costumes in the first place. It's loaded with petticoats, flounces, detached sleeves, ribbons, pearls, jewels, bows, jewel encrusted bows, gold-laced shoes, wings (which, while not technically part of the costume, are held in a way to resemble the biggest shoulderpads known to man), and a matching pink designer gun. Plus she wears that outfit anywhere, even into battle.
In Divinity: Original Sin II, Lizard NPCs generally wear the most opulent gowns, headdresses, and jewellery they can; one NPC recounts how Hannag appeared out of nowhere at his rural home in "incredible" golden robes. In lore, the Lizards place great importance on taking care of their bodies, so clothing is a way to show them off.
Princess Medea wears a couple in Dragon Quest VIII. Her "main" dress (can only be seen when the spell is gotten around) it white with gold trimming, a red petticoat, and a blue cape. Her Fairytale Wedding Dress has opera gloves, a puffy petticoat, and a lace-edged overskirt.
Princess Simona in Dragon Quest IX wears a green dress with gold trimming, dark green brocade edging the overskirt, and a large bow on the bodice.
The Emerald Princess you fight a couple times in Dream World wears at least two dresses, one a relatively simple green dress with gold trimming, and another a more fancy green dress with woven silver trimming, and a High Collar of Doom that looks as though it's made out of colored light or mist.
Wang Yuanji wears a dress that has flared sleeves with frills edging them, gold trimming, embroidery and/or brocade (depending on the exact dress), two layers of gauzy underskirts, and a Cleavage Window.
Yu Meiren wears a white dress covered in flowers, gold "scales", frills and lace.
Yue Ying wears at least two variations of a white and green dress with gold, armor, ribbons, and frilled sleeves.
Princess Sarah in Final Fantasy wears a white dress with the skirt sides slashed to show a layered green underskirt.
Hilda in Final Fantasy II wears a light blue dress with flowers embroidered on the skirt, a large ribbon wrapped just under the waist, and a long blue cape lined with embroidered purple.
Princess Sara in Final Fantasy III, at least the Video Game Remake on the DS, wears a dress of several shades of blue, a long overdress, and an underskirt of blue and gold. Some of Refia's class outfits in the remake look like fancy dresses, while they look like robes on the other characters.
Rosa of Final Fantasy IV got a rather extensive upgrade for the DS version - they added even more jewels, a tiara, and a second cape apparently made of lace, as well as lace tights and sleeves.
In Final Fantasy VI, Celes wore a white dress when impersonating Maria. The game sprites showed mainly a white dress with the skirt open to reveal the petticoat, but the FMV in the Updated Re-release on the PlayStation showed the dress as an 18th century style dress, that had loads of frills, lace, and embroidery, with a small box at the center of the scooped neckline.
Edea's dress in Final Fantasy VIII had a feather neckline, a jagged skirt, and a cape-like accessory that grew out of her back and was like a gold half circle with two white translucent strips on each side.
There are some in Final Fantasy X. Yuna's summoner dress has a pleated skirt with a white flower motif on part of it, and a huge yellow waist sash. Her wedding dress had a five-foot-long train that was trimmed and lined with white feathers, a pair of feathery wings on the back, and her veil was long enough to reach the ground and extend past her train. She also had a tiara, gloves, and in addition to her actual bouquet, there was another one in the middle of her wings. Lulu's dress has an even crazier design, with the gigantic black lace, the low-cut fur collar, and an underskirt made of practically three gazillion belts. Ironically, it's easier to pull off than Yuna's wedding dress (what with fur, lace, and even the gajillion belts being easier to find/make than hundreds of pure-white feathers), but even then a common cosplayer complaint is that they need at least two people to help them walk from the weight of the belt-skirt.
Ashe wears a couple in Final Fantasy XII. Her Fairytale Wedding Dress has loads of layers, lace, and gold trimming. Her mourning dress also has plenty of lace, symbol embroidery, and a short underskirt over the long overskirt.
Maggie, the lady of Moscet Manor in Final Fantasy: Crystal Chronicles, wears a pink skirt with gold trim, similar sleeves that are like fans, and a wide feathered headdress.
Final Fantasy Type-0 has some. Caetuna wears◊ a black underdress with a multi-colored overdress, gold trimming, a red bustier with brocade, frills on the shoulders and cuffs, a red cape, and the overskirt cut in leaf-like layers. Queen Andoria wears◊ a blue dress where the blue goes in a gradient that turns white at the bottom, the shoulders have several layers of fabric, hanging sleeves, a fancy embroidered design on the chest, a thick belt with a clover-like design, and a huge circular headdress that flares out like a skirt and has a huge strip of fabric hanging from the back. The Divas wear frilly, lacy dresses that can be seen on the games' logo.
Alfina's regular outfit in Grandia III is fairly fancy on its own (blue trimming, little holes over the chest, gauzy gloves, and a gold belt with jewels studding it), her Communicator dress is even more fancy, with a long skirt, heavy floral motif and brocade, and lots of gauze draping over it. Dahna wears a red and black dress with large purple ribbons and trimmed with gold and jewels. Hect wears a green dress with lots of red bows trimming it. Violetta wears a really short red dress (almost a jacket with no pants) with heavy trimming of black ruffles.
There is Louise◊ with a red and white dress that has trimming of gold, and edging of white fur.
Karen◊ wears a black dress that has a white frilled apron like a maid's dress, and has Giant Poofy Sleeves that have gold designs on them.
Misha◊ wears a white and orange dress that gold trimming and Skirt over Slacks where most of the skirt is translucent.
One of Julia's◊ outfits is a white and purple dress with gold trimmings, giant poofy sleeves, and a skirt where most of it is translucent.
Amelia◊ wears a blue dress with puff sleeves, golden ribbons, and belt-like decorations on the sides of the dress.
Melfie◊ wears a pink and white dress with a gold-trimmed bustier and overskirt, ruffles, and a symbol decorating the chest.
In Growlanser II, Arieta◊ wears a blue and white dress some gold trimming, lace trimming, and an overskirt cut to give a pinwheel or flower appearance.
In Growlanser III:
Anette◊ wears a red and white dress with giant poofy sleeves, gold buttons and edging, and the short frilled skirt flares out to the sides almost like a disk. She also wears a state outfit that is a conventional white dress with frills and fancy gloves.
Yayoi◊ weard a kimono with lots of lines and symbols trimming it.
Michelle◊ wears a white, black, and golden dress with lots of ruffle trimmings, and smaller poofy sleeves.
Gloria◊ wears a red dress with a narrow skirt that has a white, flared hem, white fur trimming the cuffs and the top part of her cape, gold trimming, a white vest, and a gold Giant Waist Ribbon that could actually be to ribbons.
Tricia◊ wears a green, white, and yellow dress with black trimming, opal decorations, and large rings around the shoulders and floating above the wrists.
Meleene◊ wears a black and orange dress with white frill trimming, gold trimming, and large white buttons.
Korin's◊ dress is a simple frock with ruffled trimming and white trimming over the skirt.
Melvina's◊ dress is white and black with red lining, gold trimming, ruffles around the collar, and several belts around the waist and shoulders.
Sherris◊ wears a black and gold dress with pink stocking, giant poofy sleeves with white fabric flaring out in the middle, gold trimming, pink ruffles at the skirt hem, red metal gauntlets, and huge red feather-trimmed fans.
Yurii◊ wears a pink and red kimono-like dress with gold trimming, tassels, and a huge decorative belt loaded with its own trimmings.
Wendy◊ wears a white and pink dress that is really loaded with gold trimming, has asymmetrical leggings, an extremely frilled skirt, and huge dual-layered metal shoulder guards where the top layer is even larger.
Dungeon Lady◊ wears a short pink dress with small puffed sleeves and lots of pointy trimmings.
Alyssa of Gungnir wears a pink dress with frilly sleeves, a lace-edged petticoat, a long red hooded cape, and two black ribbons with gold tassels. Her empress dress is even more elaborate. Natalia wears a red and white dress with gold trimming, black ruffles, a pink Showgirl Skirt over white puffy shorts, and also two black ribbons with gold tassels.
The "Princess 30" sections of both Half-Minute Hero games show the princesses wearing elaborate orange and white dresses. The princess of the first game◊ wears a dress with frill trimming on the collar, a two-tiered overskirt with frill trimming, and multi-tiered flounced petticoat, golden stomacher, and a Giant Waist Ribbon.
The princess of the second game◊ wears a dress trimmed with white fur, has a black leather bustier and long black leather boots, a skirt split into two sides, and a jeweled pendant that has a star/pyramid hybrid shape.
While the ladies in the Harvest Moon series often wears dresses that are at least moderately fancy, one of the grandest is worn by the goddess◊ in "Save the Homeland". It's a green, gold, and red dress where the colors blend like gradients, it has huge hanging sleeves, an overskirt, and a long jewel hanging from the center of the neckline.
Both Medusa and Palutena wear fancy dresses in Kid Icarus: Uprising. Palutena's dress is a long white robe with lots of gold trimming, and the overdress is solid white while the underdress is translucent.
Kingdom Hearts has a number of them, from the fancy gowns from the source works, to original dresses. Queen Minnie wears a pink dress with a red Giant Waist Ribbon, red ruffled petticoat, little puff sleeves, and a bunch of stars in a circle trimmed in a ring formation on the skirt. Daisy wears a purple dress with a reddish-purple petticoat, layered overskirt, white frills down the front of the bodice, gold ruffles down the side of the bodice, and a flared turned-up collar.
Princess Eclair in La Pucelle wears a blue and white dress with gold trimming, lace edging the cuffs and skirt with a line of lace down the front of the dress, and sleeves with puffs and the shoulders and flare out below the elbows.
The Legend of Dragoon has a few dresses, such as worn by the princess sisters Emille and Lisa. Emille's dress is red with an almost white skirt, and Lisa's dress is orange and yellow with gold decorations. Shana even wears a pretty white dress with High-Class Gloves near the end of disc 2, and she and Dart kiss for the first time.
Princess Irene◊, or at least the image of her, in Otomedius Gorgeous, wears a white dress with puff sleeves, fancy gloves, and an overskirt tied with a blue jewel in the front.
One of Elena's outfits in Pandora's Tower is a blue-green and white dress with lots and lots of gold trimming, and a vei-like headdress that is also heavily gold trimmed. Even her standard outfit is a bit fancy, with the heavily brocaded overdress (but a plain underskirt and sandals).
Elektra of Rune Factory Oceans wears a pink dress despite her family not being rich. The dress has lots of white ruffles, pink lace and frills, a heart decoration on the skirt, and a jewel brooch. She does take advantage of the dress by using some of the frills and flounces as pockets for her dressmaking tools.
In the Soul Series games, a few outfits were like this, such as Amy's dress in IV with the lace, frills, layering, frills, and fur neckline, or Cassandra's various white and blue dresses with the red ribbon trimmings.
Josephine in Suikoden V wears a pink dress with a red petticoat, loads of ruffles and frills, pearls trimming the neckline, a high frilly collar, a short cape, large circular earrings that almost look like mirrors, a headdress with feathers and flowers, and a Parasol of Prettiness.
In Super Mario Bros. Princess Peach's pink dress started out pretty simple, but as graphics advanced, it got more pimped out. First was a small overskirt and a brooch over her chest. Now in Super Smash Bros. Brawl, her dress has several layers of overskirts, lace trim, pleats, and gold decorations.
Daisy wears a dress that is just as pimped out, as her outfits tend to mostly match Peach's, despite her being a Tomboy Princess to Peach's Princess Classic.
Quite a few in the Tales Series games, whether it's a player character or NPC.
Estelle in Tales of Vesperia wears a white overdress dress with gold trimming, a pink gauzy underdress, and a skirt cut to look like petals of a flower.
Touhou features many "monsters" that, to fit its theme, turn into Moe Anthropomorphism forms of the monsters they are supposed to be. In cases like Yamame, who is supposed to be a spider monster, her only (outwardly) monsterous features are in the clothing she wears.
Altaecia of Wild ARMs 2 wears a pink, green, and white dress with opera gloves, puff sleeves, and lots of gold decoration.
Also from Blaze Union, are Princess Aegina wears a pink dress with slashed, gold trimming, and lots of criss-crossing threads. Princess Luciana wears a white nightie with lots of frills, and black and red ribbons with lace edging.
Although it's only seen as a sprite, the Ribbon Laced Dress by Lapin Angelique in The World Ends with You qualifies.
Princess Zelda didn't have a defined or even fancy dress, at least in-game, until The Legend of Zelda: Ocarina of Time, although the dress appeared in the instructions for The Legend of Zelda: A Link to the Past, and became her standard dress since. The dress itself has a pink-to-purple top half with a gold emblem over the chest, a white-to-rose skirt with a banner showing Hyrule heraldry hanging from a golden belt, and her golden diadem with a massive jewel (usually red) at the center. She almost always wears High-Class Gloves, gold shoulder guards attached to her chest emblem, and occasionally a cape. The younger Zeldas don't wear the big Triforce-shaped earrings that the older Zeldas do. The Legend of Zelda: Twilight Princess Zelda wears two sets of smaller earrings and has the most Gem-Encrusted, pimped out dress of all.
Defied in The Legend of Zelda: Skyward Sword, as noted in Hyrule Historia. She isn't a princess in that game, so her first outfit is a pretty casual dress, designed to be simple yet establish her as a heroine at the same time. After The Reveal, she dons a simple white dress with sandals, as one director requested her to be dressed "simply, and in white".
The GBA remake of A Link To The Past gives her sprite the fancy dress from the instructions.
Zig-zagged by The Legend of Zelda: Breath of the Wild. While Zelda does have a fancy blue dress, she rarely wears it, opting instead for comparatively simple traveling clothes (completely with pants) and a fairly simple white ceremonial dress.
From The Legend of Zelda: The Wind Waker, a grand dress is worn by Mila until her family loses its fortune, and that very dress is worn by Maggie when her family becomes rich.
And also from Twilight Princess, there is Princess Agatha's bug-themed dress, that has pink, blue, and white layers, netting over the pink, butterfly wings, and a pink headband. A Parasol of Prettiness tops it off.