Lind from Ah! My Goddess is who Heaven calls when they want something completely destroyed. She's actually a very considerate and friendly person, when she's not on the job.
To an extent, Belldandy also qualifies, especially considering that her weapon of choice is a staff and her angel uses a bow and arrow.
Maria of All Rounder Meguru meets the combat specifications as well as a sport like kickboxing allows, as a mature and elegant woman who can dismantle larger and stronger opponents without taking damage using her superior timing and technique. Her demeanor belies a mischievous and perverse personality, however.
Casca of Berserk is one of these before she goes mad from the revelation that is, being the only woman in the Band of the Hawk and carrying a lighter sword that allows her to fight more gracefully.
Farnese later on in the manga is introduced as one... but as it turns out, can't really fight. But she is shaping up to be one in more recent chapters.
Sephira in Black Cat is quiet, dignified, wields a relatively small, ladylike weapon (a cutlass), and one of the deadliest people in the series..
Black Lagoon has Balalaika, the head of the Russian Mafia group Hotel Moscow, and Sister Yolanda, head of the Church of Violence. The former was the captain of a Russian army squadron with enough manpower to potentially fight and hold on their own should World War III occur, the latter holds the guise of a nun, while actually being an arms dealer. Both of them hardly ever swear or raise their voices, maintain a distinct air of grace and respect when speaking or spoken to, and would probably kill your ass without hesitation.
Bleach: Rukia Kuchiki doesn't initially look like she qualifies for this trope: she's hot-tempered, her uniform is ill-fitting, and she's not adverse to chewing out her male friends if she thinks they're being idiots. However, this rough exterior hides an inner grace that only comes through when she fights. This inner grace has given birth to a zanpakutou that is acknowledged in the manga as a strong contender for Soul Society's most beautiful zanpakutou. Her theme is inspired by Chinese dance; her zanpakutou is called Sode no Shirayuki (Sleeve of White Snow, a nod to Chinese water dancing) and possesses a long white ribbon on the sword hilt which is swung into specific patterns to activate the zanpakutou's powers (a nod to Chinese ribbon dancing). The powers themselves are called dances during the activation command.
In Casshern Sins, Sophita simply due to the sheer grace and beauty of her combat style. In the single episode she's in, you watch her dance throughout battle, using her insanely long sword almost as more of a pivot point than a weapon, only bringing it around (rarely with both hands) for a killing blow.
Satella Harvenheit of Chrono Crusade is a borderline example—dressed in heels and an elegant dress trimmed in fur, with a high-class background and somewhat snobby demeanor, she has her moments where she fits this trope nearly perfectly, but two things stop her from being a full example. One, her attack style as a "jewel summoner" (summoning spirits to battle for her with jewels) allows her to come across as elegant and mysterious...but it also means she's not doing a whole lot of the actual fighting herself. Two, she's also a Fiery Redhead, which causes her to at times lose her cool and fight much more viciously and much less elegant. However, fellow jewel summoner and Satella's sister, Florette "Fiore" Harvenheit is a much better example. She uses her powers to summon a jeweled scythe (so her attacks are much more direct, but also show off her elegance more), and her personality during battle is cool, efficient, and unfailingly polite. She even curtsies right before she enters a battle for the first time!
Claymore has Galatea, with Teresa and Miria being close seconds. In fact, pretty much every female Claymore evolves to a Lady of War thanks to wielding swords and the professional requirement to keep a cool head at all times to avoid Awakening.
D.Gray-Man has Lenalee Lee, a friendly, softspoken Dance Battler who serves coffee in her spare time. Klaud Nine and Lulu Bell also fit, with their reserved attitudes.
Renamon in Digimon Tamers, especially in her final forms. Her partner, Ruki, is an angry Ineffectual Loner, but becomes a Lady of War when they Fusion Dance into Sakuyamon. Only while they are Sakuyamon, of course. Lalamon from Digimon Savers is pretty goofy-looking and her Crowning Moment Of Awesome is fighting with sausage nunchucks, and none of her evolved forms fare much better... until her final form, Rosemon, a dignified lady (Gainaxing aside) whose primary mode of attack is a rapier; also present in Savers is BioLotusmon, who's pretty much the same thing. Mervamon of Digimon Xros Wars leans toward this, as does her partner Nene, who actually spent some time masquerading as an elegant Digimon fighting against the forces of Dragon Land... and she succeeded at it.
Yuri Tsukikage/Cure Moonlight from HeartCatch Pretty Cure! is older than her teammates and adored for her 'elegance' in the ways she does things (like behaving herself or tending to flowers). Which doesn't go away whenever she started kicking ass with graceful movements and flips, decisive and precise blows, which hurt like hell.
Integra Hellsing from Hellsing, as per fitting for the head of her organization. Seras Averts this, however.
Pharangese/Farangis, the warrior priestess, in The Heroic Legend of Arslan. She's one of the best fighters in the cast, a beautiful, graceful lady who is one of the best with a sword and bow among the main characters, she's utterly loyal to the Prince she's been ordered to serve. (She can also drink experienced carouser Gieve under the table, without ever losing her poise.)
In Ikki Tousen, Kan'u Unchou skirts this since she uses more raw power than grace, but compared to her friend Chouhi who is in the complete territoriality of raw power, she's more like the Jack of All Stats. She has the attitude of Lady of War, though. On the other hand, her other colleague, Chou'un Shiryuu, is a complete Lady of War, not just on the polite and cool attitude, but the fact that she practically is the only girl who almost never receive a Clothing Damage in a series where clothes are made to be easily torn. That speaks a lot of her skill, reserve and grace in battle.
Inuyasha has Kikyo, an incredibly powerful miko, and Kagura, the fan-wielding villainess in a kimono.
Also Hinata Hyuuga in Part 2, since fighting style is perfect for the trope, since it's based less on brute strength and more on swiftness, chakra blocking, speed and exploiting the enemy's weakness. Combine this with her long floating hair and you get a pretty gracious female fighter.
Puella Magi Madoka Magica's Tomoe Mami. While using guns, her fighting style has a heavy emphasis on precision, grace and high calculation instead of brute force. She also tends to finish her fights with a curtsy like a Proper Lady and whip out a cup of tea to drink post-battle. In fact, one moment she replaced her precision with recklessness at the thought of having friends, which leads to her brutal death by Charlotte due to missing her weak point.
Homura falls on the Aloof Dark-Haired Girl end of the spectrum. She's always calm and never in a hurry, yet seems even more experienced and dangerous than Mami. The first witch we see her fight inexplicably explodes after she casually dodges it a few times. Time Stands Still and a Hyperspace Arsenal are a handy combination.
In Pumpkin Scissors, Alice L. Malvin amazes her sisters and the troops of Section III with how graceful and elegant her moves are during a duel that spans most of the final episodes of the anime. She can't dance on a dance floor, but put her in a fight and she suddenly becomes amazing.
Sara from Samurai Champloo. She's a blind assassin who fights with a modified walking staff. She is so good that she wounds Jin enough that he makes a desperate exit and kicks Mugen's ass from pillar to post. The only reason Sara didn't finish the job then is because Fuu threw herself between them. She would've won their second bout but pulled away from a blow that would've split Mugen in two. She does this all with an eerie elegance that makes it look as if she's toying with Mugen and Jin.
Sekirei features a few, in contrast to the many Cute Bruisers among the titular female aliens. Miya Asama, the Yamato Nadeshiko landlady of the main characters, is an exceptional Master Swordsman and teaches Musubi to not rely so much on brute force. She is also #01, The High Queen of the Sekirei. In contrast, Karasuba manages to be both this and a Combat Sado Masochist. She is a graceful Woman in Black, and rarely presents anything but an affable demeanor while carrying out her official duties......which happen to involve massive amounts of bloodshed.
Asuna from Sword Art Online, at least during the Aincrad arc. Not only is she a higher ranked fighter, she uses a Royal Rapier as her weapon, and quite gracefully so.
Kuroyukihime aka Black Lotus aka World End in Accel World by the same author. Her Duel Avatar has no feet and instead glides around just above the ground giving her movements a smooth, graceful quality. This is because her feet, arms and hands have blades in their place which will tear apart anyone short of any of the other Kings of Pure Colour or their most experienced and high level subordinates.
Octavia from Tears to Tiara is a swordswoman who teaches technique and control as opposed to the hot-blooded flailing around of Arthur.
Considering how she's very elegant but damn deadly with the monsters she summons through her cards, Ishizu from Yu-Gi-Oh! is the closest to this in a cards game.
Naomi Fluegel from Zoids: New Century/Zero is the Lady of War to Lina Toros's less-than-cute Berserker. Though they both use the same model of Zoid — the Gunsniper — Lina has turned hers into a walking gunboat, to facilitate her unrestrainedcarpet-bombing tactics. Save for a custom red paint-job (which should raise warning flags to Genre Savvy viewers), Naomi's Zoid is unremarkable. She uses it as the excellent sniping machine that it is, and she's very, very good at it.
Lady Shiva from Batman and related books. Possibly the deadliest martial artist in the world, her fighting style is a masterpiece of elegance with no wasted motion whatsoever.
In The Incredible Hulk, Caiera from Planet Hulk fits many of the requirements, being fast, graceful, and wielding an elegant weapon. She breaks from standards however, by being one of the few non-Asgardians who can not only take a punch from the green goliath, but return the favor in kind.
Buffy, from Heroes And Villains models herself on this trope fairly successfully. She greatly enjoys her various physical powers and abilities, but she is positively obsessive about her appearance at all times, and strives to project an air of elegance and cool superiority.
The Gamers: Dorkness Rising has Daphne, the Lawful GoodFragile Speedster female fighter in the game-within-a-show Her fighting style emphasizes speed and precision over brute force, and she generally behaves with more dignity than her fellow PCs, although there are times when she lightens up a bit.
Matsu in the Female Prisoner Scorpion films is an interesting subversion in a few ways. First, she's the protagonist. Second, she's a prisoner for much of the series, so stuff like social position, weapon and costume choice don't really apply, but despite this, her basic attitude exudes grace and reserve, she's aloof by nature and she's certainly stoic. Thirdly, on occasions when she does have some choice of how she equips herself, she totally rejects the idea of keeping her enemies at a distance, and opts for a knife and a Badass Longcoat with a Nice Hat, all in black, which contrives to be very feminine without being overtly sexy.
Pictured above is O-Ren Ishii from Kill Bill, Head of the Yakuza and avenger of her parents murder at age 11. She keeps that stone cold expression throughout the movie, whether it's decapitating one of her subordinates for insulting her heritage or fighting the revenge seeking protagonist to the death. She is the Expy of Lady Snowblood another notable Lady of War.
Star Wars: Padmé is this in The Phantom Menace and Attack of the Clones. She a refined, dignified noblewoman who prefers negotiation and discussion, but is a dead shot with a blaster when she needs to be. Her daughter Leia follows in her footsteps, though she is less dignified and more of a firebrand, especially in A New Hope.
Even though Selene from the Underworld can rip most her enemies to shreds with her bare hands, she always prefers killing them more elegantly, with weapons and acrobatics, if she can avoid it. This is in a particularly striking contrast to the brutal fighting styles of Michael and their daughter Eve in Awakening.
When we first see her, Jenit Sulla is the 597th's quartermaster with major Leeroy Jenkins tendencies. On Cain's recommendation, she's made a captain, and eventually becomes the first Lady General of the Imperium (the highest rank in the Imperial Guard), so clearly she had some sense knocked into her (but not literary aptitude).
The Chronicles of Narnia books have Susan Pevensie. Called Queen Susan the Gentle, she is armed with her bow and arrow, fighting more like a gentlewoman than her sister.
In Dragonlance, Laurana is an incredibly beautiful and graceful elven princess and a deadly shot with a bow.
Though usually The Vamp, Lara Raith of The Dresden Files has more than once proven that she's no slouch in physical combat either. She moves "blinding speed and utterly inhuman grace" and is implied to be even faster and just as hypnotic as her brother when fighting.
Marcone: My God. It is the most beautiful nightmare I have ever seen.
The Felix Castor books. Juliet's fighting style is often described as graceful and balletic, albeit lightning-fast and incredibly destructive (and if you pause long enough to appreciate it, she'll have already disemboweled you with her fingernails).
Honor Harrington fits this description, up to a point, as a cool, reserved, unconventionally beautiful warrior woman. At the same time, she subverts some elements of it with her preferred fighting style, the Coup de Vitesse, and while her movements are graceful, the genetic modifications she inherited on her father's side make her extremely strong, even for her already large stature.
Light And Dark The Awakening Of The Mageknight: Both Sabrina and Briza are described as fighting with deadly grace and elegance that is also a wonder to behold. The latter has the classy reserve while the former is simply aloof and focused.
Europe from the Monster Blood Tattoo series takes this trope a bit sideways. She is graceful, poised, dressed to the nines, and a duchess-in-waiting - but her weapons are electricity manipulation and a pair of staves, she's second only to the main character in how much damage she can take (a lot), and she kicks as much ass as it is possible for a single person to kick in the series.
Lyra, the mercenary Magic Knight from Passing Through evokes this even in very harsh circumstances. Despite being on the run, and in a cold and muddy forest a hundred miles from anywhere, she remains cool, aloof, beautiful and reserved. Before going into battle she takes time out to brush and arrange her hair, and never once fails to speak and act with elegance and dignity.
China Sorrows is practically the poster child for this in Skulduggery Pleasant. Calm in every situation, she's more than capable in fighting some of the strongest people in the world.
In the Shadowmarch series by Tad Williams, Queen Saqri of the Qar is known for her calmness, elegance and grace, in battle as well as in her usual demeanour.
A Song of Ice and Fire has a notable inversion in Brienne of Tarth. Nobody can dispute the "of War" bit... it's the "Lady" part she completely pounds into the ground what with being neither demure, ladylike, refined nor in the least bit pretty. She's even called "Brienne the Beauty" as an Ironic Nickname. Otherwise, she's one of the closest things to a Knight In Shining Armour you can find in the series.
From the Star Trek: Deep Space Nine Relaunch, Sirella (Martok's wife). She holds herself with grace and dignity at all times, while retaining the fierce and violent aspect of a Klingon noble. Other characters comment on this all the time. In fact, Sirella goes out of her way to be a Lady of War, and in one scene is visably unhappy when she admits that the villain's Compelling Voice caused her to momentarily lose her composure.
The Star Trek: TNG novel Gulliver's Fugitives has Shikibu, a security officer. She is described as very soft-spoken and incredibly composed, and practices Zen Archery. This involves holding a (titanium) arrow in firing position in a heavy-draw bow, with emphasis on never consciously deciding the moment of release, which happens when it happens. This comes in handy when thought-reading robot probes menace the Enterprise; since they couldn't read her intent, they didn't realize the threat. This stands as a contrast to Worf, a Proud Warrior Race Guy whose people tend towards The Berserker as a hat.
The Sword of Truth series by Terry Goodkind features a number of them. Most notably, Kahlan Amnell fills this role in the books as well as in the TV series Legend of the Seeker. It is even noted in the book that Richard was amazed that Kahlan could fight numbers of merciless assailants and yet not get a drop of blood on her white Mother Confessor dress.
Although many of them are Lady by title, the Tortall Universe rarely depicts combat as elegant (it having very much a War Is Hell message) and the Action Girls are pretty pragmatic in battle, but there are some. Keladry of Mindelan prefers the naginata to swords thanks to her upbringing in the Yamani Isles and draws admirers whenever she practices its pattern dances in public. Queen Thayet is the World's Most Beautiful Woman and wields a crossbow during her travels with Alanna, as well as learning the glaive from her future daughter-in-law.
Cordelia Vorkosigan in the Vorkosigan Saga by Lois McMaster Bujold, given that she's managed so far to take out an entire mutiny using only her brains and a stunner and end a civil war by bringing the offending man's head back in a shopping bag without ever losing her dignity.
Live Action TV
Angel: Cordelia Chase becomes one following a few lessons in swordsmanship by Angel.
In Chinese Paladin, Ling'er develops into this, as her calm, quiet and reserved personality, minimalist fighting style, and dress style contrasts with the more rambunctious and tomboyish Yue'Ru. Although Ling'er primarily uses magic as a ranged weapon, she can also handle a sword and staff.
Aeryn Sun from Farscape. Her status as official series badass is cemented in the first episode and restated innumerable times thereafter. Even after her defrosting, she continues to regularly kick metric tonnes of ass, especially when a certain child is involved. This leads to one of her many Crowning Moments of Awesome ("It's a boy. In case you were wondering.") as well as a Crowning Moment of Funny ("But shooting makes me feel better!") in the miniseries.
Kahlan from Legend of the Seeker, who frequently battles in slow-motion with knives without mussing her pretty medieval dresses.
Weaver fits the trope even better in personality and dress sense. Being a Bullet Proof Fashion Plate also helps. Although we don't see her fighting very often, because she could probably curb-stomp all of the other characters at once.
In Greek Mythology, the goddess Athena (known as Minerva to the Romans) is primarily the goddess of wisdom and crafts, but is also a goddess of defensive and strategic warfare (as opposed to Ares, who deals in offensive war, brutality, etc). She is portrayed as a "virgin goddess," meaning that either she never got laid or she never married (or both), and is portrayed as calm, wise, sly and dignified. She intervenes on the side of the Greeks on several occasions in The Iliad, and helps Odysseus on multiple times in that epic and in The Odyssey. She was also the patron goddess of Athens (which was named for her). Thanks to Athena, this trope is Older Than Feudalism.
In the Forgotten Realms, Red Knight, the Faerunian goddess of strategy and tactics (that is, her holy symbol is a chess knight), has elements of this. Her intelligence and reserve make her a natural counterbalance to the berserker war deity Garagos.
Not that there was a shortage of stylish warlike nobility on Faerun, including female nobles, due to elven influences. For that matter...
Ilsevele: Don't you dare suggest that it might be too dangerous for me, Araevin. I am one of the best spellarchers on this island and I am an officer in the Queen's Guard. note And later the sovereign in another place. After they parted ways.
Magic: The Gathering has a few, most notably Mirri, an elegant cat woman from the Weatherlight saga ("Full of beauty and grace, with a predator's instincts..."), and Jeska, a steely female barbarian from the Odyssey storyline ("My brother and I both come from Balthor's forge. Kamahl has a temper of fire. I have a temper of steel.").
Hence had the huntress Dian her dread bow Fair silver-shafted queen for ever chaste, Wherewith she tamed the brinded lioness And spotted mountain-pard, but set at nought The frivolous bolt of Cupid; gods and men Feared her stern frown, and she was queen o' the woods. What was that snaky-headed Gorgon shield That wise Minerva wore, unconquered virgin, Wherewith she freezed her foes to congealed stone, But rigid looks of chaste austerity, And noble grace that dashed brute violence With sudden adoration and blank awe?
Gali from BIONICLE. She's notable for being The Smart Guy, The Heart and having invented her own martial arts/gymnastics discipline just to qualify for this trope. Her five brother-Toa? They're pretty direct, inelegant, and can't work together well even if they're friendly. In-universe, Gali essentially invented this trope whole-cloth.
In BlazBlue, Tsubaki Yayoi uses quite some dignity when fighting with her sword. However, the more appropriate title seems to go to Litchi Faye-Ling as not only she's the adult female, her moves has quite the emphasis on fluid, graceful, classy movements, reserved chi control, and she supports it with having a nice and motherly personality to back the 'Lady' part up.
A possible choice for a female Grey Warden in Dragon Age: Origins, should she be a non-mage (and sometimes even then, taking the Magic Knight option). Most obvious if playing a dwarf or human noble. Leliana, also qualifies to an extent, as can, potentially, Wynne as a Badass Grandma version of the trope should the player give her the Arcane Warrior specialization.
Although most of her badass-itude is purely political, Queen Anora has more than a few traits of this, especially if she leads the final battle to take back Denerim.
In Dragon Age II, whether warrior or rogue, you can play female Hawke as soft-spoken, graceful, complete and utter badass. One could even extend this across the board to include a female mage Hawke too, since magic staffs now double as functional melee weapons.
Final Fantasy V has Lenna, a plucky, kind-hearted princess who can wield any weapon thanks to the job class system. She is made to look feminine in all of them and is portrayed as much more graceful and feminine than her more tomboyish sister Faris. Yoshitaka Amano and the CGs from Anthology also depict her with a sword.
Final Fantasy VI: Celes is cool-headed, graceful and looks beautiful in an opera dress. She is also a skilled fighter who can use swords, knives and maces. Her artwork even shows her striking an elegant pose while holding a sword.
Final Fantasy IX: Beatrix and Freya. Freya is calm, polite and dignified even when dealing with opponents and is an excellent fighter while Beatrix is a gentlewoman who looks feminine without being over the top about it and is a skilled swordswoman.
Final Fantasy XIII has Lightning. Cool, or even cold, and calmly collected even when taking down mooks with her sword/gun while spinning in the air acrobatically. Relatively simple clothes for Final Fantasy, yet radiates style.
Millia Rage from Guilty Gear has a quiet and completely non-brazen demeanor, and her fighting style reflects that. Her animate golden hair flows gracefully, tends to incorporate flower and wing motifs into its strikes, plus it leaves the rest of her body free to contribute to the trope with dance-like movements.
Kingdom Hearts has Aqua: dodges with cartwheels, has unusually elegant keyblades, and takes down almost every big bad singlehandedly. It does help she was named Master about 5 minutes into the game.
League of Legends gives us Ashe, who wields a bow and is using the League to gain political power and gain control of the Freljord. She's also in a marriage to Tryndamere, making an example of Guys Smash, Girls Shoot.
Her sister Seijuani might count if it wasn't for her "in your face" mentality.
Rue of Magna Carta 2 is the dedicated protector of the resident distressed princess, uses graceful 'katana' or 'shuriken' styles, and maintains an air of cool, detached competency throughout the entire story. She's also the only female on the team who shows no interest in romance and is not fanservice-y in design/presentation.
In Mass Effect 2 Samara has all the qualities: Grace, reserve, the voice of a classy woman, honor, a graceful fighting style using psionics, and a full awareness of her role in the universe wherever it takes her. Most of all, she's the only female player character in the entirety of Mass Effect who can't be successfully romanced by either Shepard. You can try, and it results in a sad, character revealing scene for Samara...but results in her proclaiming that it's impossible even if she herself desires it deep down.
From the same game, Miranda also qualifies with her elegance, calm (if cold) demeanor, and preference for biotics over firearms. And unlike Samara, she is a possible love interest.
FemShep, who despite typically acting as The Squadette during her off-duty hours, nonetheless, manages to remain focused, reserved and cool-headed at all times throughout combat situations. Particularly if playing as a Infiltrator, since she has no special biotic abilities, no offensive tech abilities and her primary weapon is simply a large sniper rifle that can punch through tanks.
Princess Kitana from the Mortal Kombat series. Her steel fans certainly fulfill the ladylike weapon requirement. She even manages to be more of a Lady of War than her mother, Queen Sindel.
Gwendolyn from Odin Sphere uses a magic spear rather than any kind of sword, but considering her noble warrior attitude and the fact that her battle outfit is based on a ballerina costume, she definitely qualifies.
In Persona 3, Mitsuru Kirijo fits the personality to a tee and favours a rapier as her weapon, but her persona skillset makes her a better example of the Lady of Black Magic. The actual female physical powerhouse, Aigis, is a Robot Girl who uses guns.
The female main character in the Portable rerelease qualifies. She even uses a Naginata as her weapon.
Project Justice's Yurika Kirishima is this. Despite being a trained Musical Assassin, she dresses and acts like she belongs in at a fancy party or in an orchestra, not a fight. She fights with her violin as if it were a rapier, and even calls fighting "meaningless" when taunting.
In Riviera: The Promised Land, Fia generally takes over the role of Healer in the group, however, she uses a rapier as her primary weapon and is the only character in the game who can use the full power of the Kiku-ichimonji, making use of the attack "Oboro-garasu". Her Overdrive skills also carry an "air of grace" with them, and are named after musical terms (Vivace, Cadenza, Presto, Brilliante).
Karin Koenig in Shadow Hearts: Covenant fits this role well, alternate costumes be damned. Her weapon of choice is the rapier, she learns new battle techniques by collecting Wagnerian manuscripts and genuinely fights in a graceful manner as befitting the role. Karin is also the female lead of her game.
Xiuying from Shenmue. Soon after making her debut in the second game, she curb stomps Ryo, effortlessly avoiding his attacks and putting him in his place with bare minimum force. Later, when the first fight against Don Niu on Kowloon goes awry, she steps in as Ryo blacks out. And from the tone of Don Niu's yell after the fade to black, she pounds him in short order as well. Oh yeah, in both times she's wearing a simple but elegant Chinese dress.
The Street Fighter series. Chun-Li also really counts. While most would associate her with straight-on Action Girl, she moves gracefully and fluidly in each of her attacks. Her fighting style does also quite resemble Tai Chi Quan, and she possesses chi control as shown in her Kikouken or Kikoushou.
Chris Lightfellow, AKA the Silver Maiden, from Suikoden III. Graceful, upper-class and with a social ineptitude that expresses itself as cold arrogance, the Supreme Commander of the army in a country where female soldiers are unheard of. Amusingly, the gang of kids who model themselves after the knights interpret her as the White Magician Girl sidekick to one of her male colleagues.
In Suikoden I, there's also Odessa Silverberg, who is quite handy with her bow and since she's born from a family of strategists, utilizes lots of reserve and tactics in combat. It's also speculated that in the first game, her growth rate is somehow the best in the game. Unfortunately...
In turn, there's Raphael's adoptive daughter Amy; she takes after him in terms of swordplay and she's just as graceful with her rapier, if not moreso.
Jun Kazama from Tekken. She is usually a Mixed Martial Arts user, but it's mainly based on Aikido with emphasis on grace... and she also utilizes precise counter-holds in battle. Personality-wise, she's described as demure and focused, but if pushed far enough, especially if her child is in danger, she'll calmly open a can of whoop-ass to even the Devil himself. Her Spiritual Successor Asuka Kazama also uses Aikido, but subverts it that her fighting style is more direct in-your-face and brash, like her personality.
In Touhou, Sakuya Izayoi is a Meido version of this trope. One just doesn't call her Perfect, Elegant (Ninja) Maid for nothing.
Scarlet Weather Rhapsody brought us Iku Nagae, who fights using a frilly scarf and whose attack poses resemble dance moves.
Raquel Applegate in Wild ARMs 4. A Mighty Glacier with a tragic past, a cool demeanor, and a quest for beauty and friendship.
Rosalina in Super Smash Bros.. While Peach and Zelda (the other regal fighters) take a more athletic approach to their attacks, Rosalina's style is far more elegant and dance-like, fitting well with her status as The High Queen. Her partner Luma, on the other hand, is the one that dishes out the rougher stuff.
In The Whateley Universe, while Fey of the Super Hero School Whateley Academy is a mage, she fits this trope pretty well. She's been given a magic scimitar which she learns to use, and she's learning to wield the bow. She's literally a princess, since part of her is an ancient Sidhe queen. And her fighting style is Tai Chi with grace, since her Faerie glamour won't permit anything else.
In Worm, Contessa is described as extremely graceful in combat, and incapacitates the Chicago Wards and Weaver mainly by letting them hit each other, without even getting dirty.
There's also Suki and the other Kyoshi warriors, as well as, now long-dead, former Avatar Kyoshi herself. All wear dresses that resemble modern day war fatigues, make-up that serves as war paint, and metal fans which can be used as ranged throwing weapons. Suki even teaches Sokka their fighting methods, including making him wear the dress and make-up, and while originally rather sexist and dismissive of them, he comes to respect them pretty quickly.