The Treue (German for "loyalty") Unit in Super Robot Wars Original Generation, and it's not just "coincidence" like many others; the unit is, for some reason, for females only.
Sailor Moon and her Sailor Senshi, as well as many of their villains: the Ayakashi Sisters, the Witches 5, the Amazoness Quartet, and the Sailor Animamates.
The titular Otome of Mai-Otome, although there is a Technobabble explanation for their powers being exclusive to female virgins. While an Otome usually works alone, doing her Master's bidding, the Five Columns (who have no Master) are an actual team.
Fanon in regard to the Dirty Pair frequently implies, for reasons we can only guess at, that the entirety of the 3.W.A.'s field-agent personnel are female.
Integra, Accela, Sylvia and Celica make up the R.U.C.'s PROCEED squad in Solty Rei.
The three female pilots on the Nadesico worked as an Amazon Brigade (Amazon Flight, really) before joining the crew, and usually act as a unit while Akito or Akatsuki are off doing their own thing during the series. The ship's bridge crew is a couple of non-commissioned adjutants and one girly XO away from this trope as well.
Jail Scaglietti's "Numbers" in StrikerS count as well. (no pun intended)
Although that one had a rather disturbing justification: Scaglietti needed his minions to be female so that he could impregnate them with clones of himself.
Simeon's girl squadron in NEEDLESS, consisting of Setsuna, Mio and Kuchinashi. Don't be fooled by their cuteness.
The Red Tails Gang from Beelzebub are an all female gang of Japanese Delinquents known as the strongest ladies of Kanto, and for good reason too! Their leader Kunieda Aoi, nicknamed the Queen, is responsible for keeping the men's "grubby hands" off the other girls. Their weapons range from guns, to baseball bats, to bokken.
In Sound Of The Skies, the Helvetian Army fields all-female tank crews, the main characters being the 1121st tank platoon.
In Sekirei, any group with multiple Sekirei is this by default. Most noteworthy are Minato's Battle Harem, Sanada of the West's Power Trio, and the Discipline Squad, while the other two major groups (the South and the East) don't function as units to the same degree. The first incarnation of the Discipline Squad remains legendary for their strength, as well as having been the one version to include The One Guy.
Any armed group by default in Y: The Last Man. The best example is probably the IDF special forces led by Alter; the actual Daughters of the Amazon are fairly disorganized and gang-like.
A short-lived offshoot of Marvel's The Avengers, the Lady Liberators; but they were secretly being manipulated by the Enchantress.
Another Marvel group, the Femizons, from a future militant Lady Land society. When that timeline was erased, a present-day misandrist named Superia tries to create her own Femizons a few centuries early by gathering supervillainesses and female Mad Scientists to repopulate the world, right after she sterilizes everyone else, of course.
The Grapplers were super-strong wrestler/criminals.
Femforce from AC Comics, which seems to exist mainly as fanservice for its creators and readers.
The Star Sapphire Corps from Green Lantern. Subverted in the fact that the Star Sapphire's version of Ion or Parallax, Predator, is male.
The recently formed Sisterhood of Mutants in X-Men
The Black Dahlias from The Order, who Veda described as "Tim Burton sponsors a women's golf team."
Katarina Dante's pirate crew and Monique le Fanu's vampires (who now presumably follow Lulu Romanov) in Nikolai Dante.
In the "X-Tinction Agenda" crossover storyline Uncanny X-Men books, artist Jim Lee depicted the law enforcement of Genosha as being mostly female and incredibly hot.
The The Man From UNCLE comic book had an unrelated backup feature, Jet Dream. Gender-flipped Expies of Blackhawk, Jet and her international teammates Marlene, Petite, Cookie and (sigh) Ting-a-Ling were Hollywood Stunt-Girls who also moonlighted as a crack team of all-girl aviators, spies, and commandos.
Battlefields: Night Witches, by Garth Ennis, is a fictionalized account of the USSR's "Night Witches" (see Real Life, below) during World War II.
Sin City has the Old Town girls. They've teamed up a lot with the male protagonists but there are male-less Old Town stories out there. Also keep in mind that these girls are tough enough that both the cops and the mafia are afraid to mess with them.
The Airmaidens, the elite personal squadron of Valkyrie in Airboy.
In Astérix and the Secret Weapon, the Romans raise a legion of women to fight the indomitable Gauls, taking advantage of the Gaul's rule that they Wouldn't Hit a Girl. They do seem to have a problem understanding the words "order" and "discipline."
The 2013 (adjectiveless) X-Men comic will feature an all-female X-Men team: Storm, Rogue, Kitty Pryde, Rachel Summers, Psylocke and Jubilee.
The Marvel Now relaunch of The Defenders, Fearless Defenders, features Valkyrie putting together a team of super-women to be her new Valkyrion. Right now it includes Dani Moonstar, Misty Knight, Hippolyte, and Annabelle.
Nth Man The Ultimate Ninja featured the KGB Swallows, a team of attractive female Soviet agents trained in both espionage and combat.
Fan Fiction
The Replica Elite from Aeon Natum Engel, although their femininity is only skin-deep; they act no different from FEAR's male Replica Elite.
Discussed and inverted in the MLPFIM adult fic Xenophilia. Between the gender disproportion of Equestria and the matriarchal system resulting from the two immortal princesses, Men Are the Expendable Gender is inverted, along with many social norms. That means the buff pegasi and unicorns guarding Celestia are the local equivalent of Bodyguard Babes.
The Daughters of Manehatan from The God Empress Of Ponykind; the Western Rangers may qualify as well, since we haven't seen any colts serving that Legion.
In keeping with the base canon, Armored Core + Muv-Luv Alternative crossover fic Project Ignition, all of the Lynx who are actually affiliated (Not Independents, Not Torus, and not Aldra) with the Interior Union are female. A special note goes out to Kagami, Lunaterisa, and Aerilynn, who are generally known as "The Three Valkyries", who are an elite squad piloting stolen Super Prototype.
In Terry Pratchett's Discworld fandom, a whole body of work has been presented about the Last Detail, the all-female combat unit introduced in Monstrous Regiment. This largely results in femslash about Polly Perks and the vampire female Maledicta, but all the fictions emphasise what a coherent, hard, fighting unit they are.
The new generation of female Assassins are also badass, either taken individually or working as teams. Lady T'Malia, Alice Band, Madame Deux-Epées, Remora Selachii, miss Smith-Rhodes and Jocasta Wiggs are the named Assassins in Pratchett's canon. Other fanfic writers have expanded on these characters and added new ones, such as Ruth N'Kweze, Joan Sanderson-Reeves and Davinia Bellamy. (for an example, see The Graduation Class)
Film
Missy, Chrissy, Justice and Sissy in Jay and Silent Bob Strike Back. Of course, they're more a band of sassy jewel thieves.
Transformers: Revenge of The Fallen features the Arcee Sisters, consisting of Arcee, Chromia, and Elita-1. Though they have minimal screentime, they only ever appear as a unit. Canon, different writers, etc. differ on whether she's three individuals or one with three bodies.
The Sisterhood of Kira Earta, an order of warrior priestesses in Swordcraft.
Literature
In the Star WarsExpanded Universe we have the Mistryl Shadow Guard, a group of whip-wielding mercenaries from a doomed civilization, and the Hapes Consortium, an interstellar cluster of Amazons whose (formidable) army and navy was solely composed of females.
In The Firebrand, Marion Zimmer Bradley's retelling of The Iliad from the perspective of Kassandra, we have... the original Amazons. By the end of the book, they more or less die out, logical with the feminist bent of the novel and the way that the cult of patriarchy was sweeping the nation.
In Dune the Bene Gesserit can fight with nearly superhuman capability if necessary, and Heretics of Dune introduces the Honored Matres. Leto II justifies this trope when he forms the Fish-Speakers in God-Emperor of Dune: he believes their maternal instinct will prevent them from succumbing to bloodlust or quests for power, and they're a temporary army since they're all about him, so they'll lack a unifying force once he dies. It's all part of his Golden Path for humanity.
The Maidens of the Spear and Elayne's personal bodyguard in The Wheel of Time books.
The Discworld novel Monstrous Regiment features a squad consisting entirely of Sweet Polly Olivers. The first clue is right there in the title: John Knox once wrote a pamphlet called "The First Blast Of The Trumpet Against The Monstrous Regiment Of Women".
The protagonist of The Assassins Of Tamurin is recruited for a secret organization of this type.
Isaac Asimov's short story "Shah Guido G." features an all-female police force known as the Waves. However this really had nothing to do with the plot, being part of a clumsy and long-drawn-out build up to a punning punchline.
In The Stainless Steel Rat's Revenge Special Corps agent James Bolivar "Slippery Jim" DiGriz lands on a planet once run by women (until they were usurped by a male revolutionary party working in cahoots with galactic invaders). He teams up with the resistance – former members of the military who are of course fit, shapely young amazons – much to the annoyance of Jim's lethally-armed and dangerous wife.
The Mord-Sith from The Sword of Truth, who are the sworn protectors of Lord Rahl, as well as his expert torturers. They perform... other services for him, they act as his bodyguard, are capable of beating up squads of elite soldiers without breaking a sweat, have a magical torture device / weapon / awkward phallus thing called an Agiel, they're made via a truly horrifying Break the Cutie indoctrination process, are probably the second most feared thing in all of D'Hara, only behind the Lord Rahl himself... oh and they can capture your magic and use it to torture you. They've driven one member of the main cast insane.
The Longwing dragon captains in the Temeraire series could be a sort of Amazon Brigade - Longwings almost exclusively select female captains (it is implied that on occasion one will accept a male grudgingly, but none have been shown yet).
In China several centuries before the events in the books, women were permitted to serve as combat dragon riders by Imperial Decree after a Sweet Polly Oliverenlisted to spare her fatherand stopped an invasion after bonding with a dragon. Between conscription and the willingness of families to get rid of daughters, by the time Cpt. Laurence and Temeraire arrive the Chinese government had long since thrown up their hands and made their Dragon Corps an exclusive female preserve.
Percy Jackson and the Olympians has the hunters of Artemis, a group of girls that travel with the goddess Artemis and are allowed to live without aging as long as they remain maidens for ever. They happen to be extremely handy with a bow, and are strong fighters all around. The Heroes of Olympus also reveals that the Amazons themselves are still in business, running Amazon.com.
The Queens' Wing can be a pretty effective Thread-fighting force in the Dragonriders of Pern novels, particularly once they caught on to how easily a queen dragon can boss around any other color.
Thandi Palane's self-styled Amazons (descendants of genetically engineered Ukranian supersoldiers) in the Honor Harrington universe.
Much like in Ursula Vernon's webcomic Digger, her Black Dogs series contains a race of matriarchal hyena people. Their appearance is more brief and their role much less pivotal, but from what is seen of them, their warriors and hunters are all female. It is also observed by the protagonist that the females are larger and more physically intimidating than the males.
In Sewer, Gas & Electric, a female Royal Navy officer averted an assassination attempt and, in return, asked Queen Elizabeth II for command of a submarine. When the navy brass told Her Majesty that having a woman take charge of a sub was unthinkable due to conditions on board, Her Majesty got peeved; four years later, the H.M.S. City of Women was launched with an all-female crew.
A rare non-Fantasy or Sci-fi example: thriller writer Brad Thor created a "detachment" of all-female Delta Force members for his most recent Scot Harvath novel Foreign Influence, which spawned the sequel/spinoff The Athena Project.
Neal Stephenson's Science Fiction novel The Diamond Age has Nell's "sisters", or "Mouse Amy", a group of soldiers/engineers/political leaders that finally becomes a new sovereign.
The soldiers of the Hames in Jane Yolen's Great Alta Saga. Before the invasion, they were among the most honored warriors in the Dales, and not a male in sight.
David Weber's WarGod series has a couple of different examples. The most detailed example are the Sothoii War Maids. Free towns administered by women in the very patriarchal Sothoii society they are required to supply levies in times of war under the Kingdom's feudal military structure and by tradition they field all female fighting forces. Considered outcasts by Sothoii society as a whole but supported strongly by the Wind Riders, the elite of the Sothoii military.
In the Aubrey Maturin novel The Far Side of the World, Jack and Stephen are rescued/taken prisoner by the all-female crew of a Polynesian twin-hulled craft. They also have an extreme case of Does Not Like Men, apparently castrating their male captives as a matter of course.
The Marvelous Land of Oz features Jinjur's army. A revolutionary army composed entirely of young girls dressed in World War 1 era uniforms. This being one of the Oz books, they're about as deadly of a fighting force as a kindle of kittens. They find early success against the Emerald City's army, an old man who Wouldn't Hit a Girl, but are in for a nasty surprise when Glinda brings in her own all-female army who actually know what they're doing.
The Sisterhood series by Fern Michaels: The Sisters, Sisterhood, or Vigilantes (whatever you like to call them) can be considered this - as long as you don't include Charles Martin and the Big Five or the Five Musketeers. The last book Home Free subverts this trope by having the Vigilantes recruit male members into their ranks at the end.
The eponymous Bunch in The Bad Bunch by J.T. Edson; an all-female gang of outlaws as dangerous and ruthless as any men.
In Tunnel In The Sky, Helen Walker is a captain in the Amazon Corps.
The qawHaq'hoch, in the Star Trek: Voyager Relaunch, a Klingon cult consisting of female warriors only. Interestingly, it's never explained why they only accept females. Possibly it's "just tradition" - but it's one they're quite serious about. They draw attention to their status as an Amazon Brigade by using a symbol for birth (Ie., an aspect of life exclusive to women) as the glyph signifying the correct tunnel to their headquarters.
Harry Potter has the Holyhead Harpies, an all female Quidditch team.
Legacy of the Dragokin: The Kthonian Knights are supposed to be this because they hate men and wanted to kill all of them but Jihadain let Ravage join because he's Fury's protective big brother and she wants him to join.
Live Action TV
The three main members of Charlie's Angels, in either the TV series or the movies.
Another villainous example: The Hanarangers of Kakuranger
The Slayers after season 7 of Buffy the Vampire Slayer. Every slayer is female and all of them are walking anti-vampire weapons.
After the events of season eight Kennedy didn't just sit on her hands. She creates Deepscan, giving Slayers with no further purpose a job in bodyguard work.
One episode of Stargate Atlantis featured an Amazon Brigade providing most of the muscle. Colonel Sheppard and Dr. Beckett were thoroughly delighted to be working with them.
Stargate SG-1 had the Hak'tyl, a Jaffa tribe hiding from the Goa'uld Moloch.
Star Trek: Enterprise was the first to reveal that the Orion women, far from being the slaves portrayed in the other series, actually control their civilization with a male-attracting pheromone that gives other women headaches. The only one unaffected by them is Trip.
A villainous example were Saladin's assassins in Robin Hood, a squad of women who were sent to kill Prince Malik.
Music
Emilie Autumn's riot grrl-esque band The Bloody Crumpets (or at least their stage personas). Even Aprella. Hell, their catchprase is "Fight like a girl!" As a phrase of empowerment, that is.
Klymaxx is also this.
Myth and Legend
The White Tights of urban legend, a group of blonde, white-cladsniper women with a hate-on for the Russians. Allegedly formed of women from Eastern European countries such as Estonia and Latvia, where hating Russia is a national pastime. According to rumors, they fought in Chechnya on the Separatist side.
In Chinese folklore, the widows of the Yang generals during the Song Dynasty. When most of the Yang menfolk were killed defending a fort from Liao invaders, the women of the clan took up arms to confront the Liao army. This has been dramatised in films such as The Fourteen Amazons and The Legendary Amazons.
Although the Valkyries of Norse Mythology were primarily focused on collecting the dead, there were plenty of attestations of the female bands fearlessly engaging in battle.
The Sisters of Battle in Warhammer 40000, a force of power armoredreligious fanaticswieldingbolters, chainswords and flamethrowers. They began as an all-female sect tricked into becoming the bodyguard of the insane High Lord Vandire, who seized control of both the Administratum and the Ecclesiarchy and plunged the Imperium into a bloody civil war. The Daughters eventually discovered his treachery and ended the conflict by taking Vandire's head, and though the reforms that followed forbade the church from keeping "men under arms," this obviously didn't apply to the newly-renamed Sisters of Battle. Since then the Adepta Sororitas serve as both the fighting arm of the Ecclesiarchy and the Chamber Militant of the Inquisition's Ordo Hereticus, a force tasked with ensuring that such heresy never happens again. And in a slight subversion of the trope, many Battle-Sisters (particularly the veterans and leaders) show the obvious scars that a lifetime of fighting in the 41st Millennium would entail.
Imperial Guard regiments are almost uniformly single-sex units, and according to the Ciaphas Cain novels about 10% of the Guard's forces are all-female regiments. Mixed units do exist, but are usually the result of depleted regiments being combined together, as was the case in Cain's own Valhallan 597th as well as the Tanith First and Only. The gender segregation is mainly for practical reasons, as shown when Cain has to deal with increased fraternization between troopers and some unforeseen complications.
The Dark Eldar's Wych Cult is made up of elite warriors who help capture prisoners during slave raids, then fight the captives in gladiatorial combat for the Dark Eldar's bloody amusement. Wyches take pride in their appearance and emphasize spectacle during their arena matches, so they do battle against the likes of Space Marines and Tyranid Warriors while wearing anti-clothing. Males are allowed to join the cult, but they never manage to progress far in it - they simply lack the proper "style and poise" to become a true champion.
The Sister of Silence in the Horus Heresy books may have been the precursor to the Sisters of Battle, but they had a signifigant difffernce between them and their ancestors- they were composed entirely of Blanks.
They're still around in the 41st Millenium, but they crew the Inquisition's Black Ships and manage rogue psykers rather than engage in direct combat.
The Dark Elves of Warhammer Fantasy provide two examples. Witch Elves are an all-female cult of attractive, lethal fighters in chainmail bikinis, who serve a god of murder, indulge in combat drugs, and bathe in blood to preserve their beauty. Dark Elf Sorceresses also qualify due to a prophecy that a male sorcerer would kill their Witch-King, who quite naturally banned men from practicing magic. There are male sorcerers, but they keep their heads very far down.
The High Elf Everqueen is protected by the Maiden Guard.
Dragon Dice has an entire playable race of Amazons. The only race in the setting created directly and solely by the male deity, they can be played as either an entire army of Amazons, or as an elite maneuver/ranged combat unit in a larger force.
In Rifts, Free Quebec has mastered the creation of the uber-powerful Glitter Boy powered armour. Female pilots lobbied for years to get their own distinctive style of armour. Enter the Glitter Girl recon/special forces unit. More dangerous than the male variant due to the pilots being older and more experienced. Notable squads inclued the Harlots, the Harpies, the Vixens, and the Riot Girls.
And don't forget the Blind Warrior Women, who look simply irresistible.
And the city of Manoa in South America, with literal Amazon brigades.
Werewolf The Apocalypse had the Black Furies, a tribe made up entirely of female Garou who worshipped Artemis as an aspect of Gaia. Of course they'd associate with men for production of new children, but male offspring were passed on to other tribes. There are male Black Furies, however; Metis (deformed children of werewolf-werewolf matings) born to Black Fury mothers are accepted into the tribe regardless of their gender.
The Sisters of Mercy from the Feng Shui supplement "Glimpse of the Abyss" are a convent of Nuns With Guns based in the Netherworld who hunt down and kill those whom their Mother Superior deems to be deserving of the respite of death from the suffering the Sisters believe that life is. Of course, those whose names end up on the Rolls of Mercy and are targeted for "deliverance" often aren't so keen on dying. Also from "Glimpse of the Abyss" are the Shiva Squadron, a band of distimed eight-armed warrior women who have made it their mission to hunt demons.
Legend of the Five Rings has two examples in the matriarcal Utaku and Matsu families. The Utaku family (formerly known as the Otaku family) has the Shiotome, or Battle Maidens, an elite unit of shock troops that ride into battle on horses the size of Clydesdales. The Matsu family's elite Lion's Pride is an all-female unit of samurai women that specializes in finding and killing the enemy general and his command staff.
Exalted has the Brides of Ahlat, the Southern God of War. Completely female, sworn to remain virgins, and symbolically wed to Ahlat himself. They're consider to be Elite troops and thus not to be messed with.
Exalted also has the Tya, a group of women in the West who reject the usual gender roles for the region to take on male ones-which is more than symbolic, as the ritual wards away the spiteful goddesses known as the storm mothers (they hate any woman prettier then they are, which includes everyone that is not a storm mother). They are treated in society more as men than women, actually.
In 2nd Edition Dungeons & Dragons, several of the "Complete Class" supplements included an Amazon character kit.
Mage Knight included a subset of Amazon figures in one of its more Steampunk factions, the Black Powder Rebels. They weren't necessarily more powerful than any other group or faction (except for the Amazon Draconum, which was borderline broken.)
In Mutant Chronicles, at least three factions have Amazon Brigades: Bauhaus has Etoiles Mortant, Imperial has Mourning Wolves and The Brotherhood has Valkyries and Vestals. Mishima was supposed to have an elite unit of female warriors, the Kikigomae Sohei, as well, but Publisher Existence Failure caused them to be limited only to a concept drawing and a mention in the rulebook for Warzone: Universe Under Siege as no figures were produced.
Dungeons & Dragons: The Tome of Battle has lots of fluff about secret organizations of Walkers of the Sublime Way. One of which is the 80 Empresses.
The Amazones of Bloodlust, called Sekekers, are used to mutilate themself and are thus quite ugly. However, some beautiful young girls form a elite unit called the Chrysalides, and are trained to fight half-naked.
Shadowrun has the all-female street gang Desolation Angels that are active in many American cities. The gang is known to hunt bug spirits with great enthusiasm for some reason. The reason is simple: they are Mantis spirit hosts.
Legends Of The Wulin has two: The Resplendent Phoenix Society, who seek to embody feminine perfection, and the Blood Wind Cult, an all-female sect of assassins.
Sports
The Finnish national men's ice hockey team is known as The Lions. The women's team is known as The Lionesses.
Theatre
You better not forget those flying horse-riding shieldmaidens in the winged helmets from Die Walküre.
Amaluna has both Amazons and Valkyries.
Video Games
Any naginata unit in Kessen III.
The various incarnations of the "Women's Team" in The King Of Fighters. Its ranks include: King, Mai Shiranui, Yuri Sakazaki, Kasumi Todo, Chizuru Kagura, Li Xiangfei, Hinako Shinjou, Blue Mary Ryan and May Lee.
In KOF 2003 Athena Asamiya, Hinako and Malin had their own all-girls group, the "High School Girls Team". Similarly, KOF 2002: Unlimited Match (a remake of the original KOF 2002) gave us two other all-girls team: the "Pretty Girls Team" (Xiangfei, Hinako and May-Lee, who was a member of the original Women's Team in the first 2002) and the enemy-only NESTS team (Kula, Foxy and Diana)
In Warcraft III, the Night Elves' military, the Sentinels, is comprised solely of women because the race's men study druidism and spend centuries at a time asleep in the Emerald Dream. Over the course of the campaign male Night Elves join the battle, but only as support casters (at least until the Druids of the Claw shapeshift). By World of Warcraft the gender divide is eased so that Night Elven females can become druids and men can become fighters, but the overwhelming majority of Sentinels are still women, while there is only a single male priest of Elune seen in-game.
As probably an inverted reference to this, the Blood Elf guards are all male.
In Final Fantasy IX, Alexandria's army consists almost entirely of women. The only males are the Knights of Pluto, a squad consisting of a mere 9 men, including playable character Steiner, who serves as their captain.
The military of the city of Troia in Final Fantasy IV likewise consisted entirely of women.
Some players (like me) try to get one of these going in any game that gives a party, whether one you fill with your own rolled characters (Wasteland), or with a cast (Final Fantasy XII. Some games make this easier than others.
Luna's subordinates in Soul Calibur 3's Chronicles of The Sword, the Klessirpemdo, are a quartet of elementally-themed female minions: Lupi (Fires of Hell), Heal-Do (Water of Origin), Elua (Wind of Creation) and Aege (Earth of Foundation). Their leader Luna is probably meant to be Spirit/Aether or something.
Unreal II The Awakening features such a brigade in the form of the Liandri Angels, an all-female "mercenary" cyborg squadrons, the game's toughest Mooks. An in-game dialogue maintains that females are naturally ruthless and that that has been the reason behind the creation of these squadrons.
Diablo II starts the player out in the Rogues' camp (a reference to the female-only Rogue class from original Diablo). Everyone permanently living there is female, from the blacksmith Charsi to the matronly high priestess Akara to the guard captain Kashya. They're staying in the camp because they had been evicted from their monastery after Diablo's minions took over and mind-controlled half their numbers, whom you fight throughout Act I, and who are also all female.
Siege Of Avalon has the Blood Roses, an order of female knights.
The Aeon military in Supreme Commander comes very close-game background states that Aeon women are just plain better at battlefield command, with very few males qualifying for command. Possibly a coincidence, but the foremost commanders of the UEF and Cybrans are women as well.
In the first Knights of the Old Republic, an away team composed of a female player character, Bastila Shan, and Mission Vao. In the second, a female player character, Mira, and Visas Marr (especially if you have progressed far enough to make Mira a Jedi).
Mass Effect - The asari are a One Gender Race of women, and due to their extremely long lifespans (upwards of a thousand years) asari commandos train for a hundred years before they go on active duty. In addition, the asari are also natural biotics. The warrior turian race (where military service is the entire society and military service is directly responsible for citizenship) have a saying: "The asari huntresses are the best warriors in the galaxy. It's a good thing there aren't that many of them."
Additionally, a field squad composed of a female Commander Shepard and any two of Ashley Williams, Tali'Zorah nar Rayya, or Liara T'Soni also qualifies as an Amazon Brigade, particularly at higher levels. And in the sequel, Female Shepard with Jack, Kasumi Goto, Miranda Lawson, Samara, Tali, Morinth, and Liara T'Soni (in DLC) counts.
And in the third game, Female Shepard with Ashley, Tali, Liara and EDI, or the Omega DLC squadmates.
In Mass Effect 1, should you refuse to recruit Garrus, kill Wrex and sacrifice Kaidan on Virmire as a Femshep, an Amazon Brigade squad will be your only option.
Ratchet & Clank Future: A Crack in Time has the Valkyries, an army of ace pilots and shock troopers comprised entirely of female aliens. Despite the name, male versions exist but, according to a piece of Galactic Trivia, were banished after failing to ask for directions during their pilgrimage after their home colony was decimated by a supernova.
The Galactic Rangers are apparently all female as well, although whether that's correct or simply the squad leader unnecessarily taking the Mickey isn't explained.
Project Justice has the Seijyun High trio of Akira, Yurika and Zaki. Closer to the definition of this trope is Zaki's gang, the Ladies Team, though a good number of the gang's members may not meet the "be at least moderately attractive" description.
Crimson Skies has the Medusas; an all female pirate gang.
Dragon Age: Origins has the dwarven organization The Silent Sisters, a group of dwarven women who cut out their own tongues and devote themselves completely to martial training.
You can also assemble your own all-female team with any combination of Leliana, Wynne, Morrigan and Shale.
Dragon Age II - female Hawke and any three of Isabela, Merrill, Bethany, Aveline or Tallis (Mark of the Assassin only).
In addition, one of the night-time gangs, the Invisible Sisters, are an all-female group focusing on attacks from stealth.
In Baldur's Gate II: Throne Of Bhaal, one of the three guardians for the final seal is an entirely female group composed of Y'tossi (a marilith), Nalmissra (a succubus), The Hive Mother (a beholder), Amerilis Zauvwir (a drow cleric), The Huntress (an archer) and Xei Win Toh (presumably a kensai).
Also possible for your own party: in BG1 you have a female PC and (depending on your alignment) any combination of Alora, Viconia, Dynaheir, Imoen, Jaheira, Branwen, Faldorn, Shar-Teel, Skie and Safana. BG2 and ToB feature the return of Imoen, Viconia and Jaheira, along with new characters Aerie, Nalia and Mazzy.
Interior Union in Armored Core, every one of the Lynxes for hire is a women, and unlike Bernard And Felix, more than willing to let you use them as consorts.
In Neverwinter Nights 2 it's possible to create a balanced all-female team using a female Knight-Captain built as a tank, Qara the sorceress, Neeshka the rogue, and Elanee the druid. Act II adds Shandra Jerro as a guest star fighter, and the githzerai cleric Zhjaeve.
Even easier in the second expansion, Storm of Zehir, which lets you handcraft your own party.
Sakura Wars. This is the entire point of this Dating Sim / Tactical RPG series. With a dash of That One Guy thrown in as your player avatar (Ogami in the first four games, and Shinjiro in the fifth game.) Your party's effectiveness in battle is dependent on how strong your bonds with your Amazon Brigade are... in addition to how well they get along with one another.
You get an achievement for using an all-female squad in the XCOM: Enemy Unknown remake. Otherwise, there's absolutely no difference (e.g. a female Heavy can carry a heavy plasma gun and a rocket launcher just as easily as a male Heavy, despite not looking the part).
The mmorpg game Scarlet Blade emphasizes in this, as the game focuses on genetically enhanced females, and there are no male playable classes.
Webcomics
In El Goonish Shive, Ellen, Grace, and Nanase form a temporary Amazon Brigade during the Painted Black arc.
The Amazons of Chasing the Sunset. Their foremothers were ordinary women who took up combat to save themselves: by the time we meet them in the comic, they are blue-skinned warriors who reproduce asexually.
An internet offshoot of Marvel UK's Warheads series, Loose Cannons tells the tale of an experimental all-female group of Warheads (paramilitary units sent through spacetime wormholes to gather technology and magical artifacts for the Corrupt Corporate Executive leaders of the sinister MysTech; think Stargate SG-1 as mercenary raiders hired by a cabal of evil sorcerers) called the Virago Troop— who bring back more than they bargain for from an After the End future.
Completely justified in Digger. The hunters and warriors of the hyena tribe are all female because they, just like real-life hyenas, are larger and stronger than the males.
Outsider has the Loroi, a species of space elves with an all-female military. Justified, since only one in eight Loroi are born male, which they consider a basic adaptation for a warrior species, since it allows them to create some massive population booms where necessary, or avoid overpopulation by restricting access to males.
Further justified by the fact that Loroi females are actually the bigger and stronger members of the species. The males are child-sized.
Illyra, Elysia, and Occela form the basis of a budding Amazon Brigade in Rumors of War. Given that the setting is based on Greek Mythology, one or more of them may actually be Amazons.
Though not a brigade specifically, the female cast members of Something Positive are both more violent and most of the time, stronger than the male cast members (although how much the male members are willing to fight in general may have something to do with it). The basic rules seems to be that if somebody has a pair of breasts and is reasonably intelligent, she can probably kick your ass.
Team Kimba of the Whateley Universe is really close, considering that their one 'boy' was born a girl named Hannah. The Whateley Academy Martial Arts Cheerleaders are all-girl but not tough enough to be a true Amazon Brigade.
In the 1979 animated Flash Gordon series from Filmation, Princess Aura had an elite guard of female warriors under her command known as the Witch-Women.
The Amazons (surprise, surprise) in Motorcity, with their leader Foxy. Claire briefly teams up with them, and Julie pretends to be interested in joining.
In comparison to the previousgenerations, the main characters of My Little Pony: Friendship Is Magic are prepared to get into a fight and handle themselves well if they have to. The G1 ponies seem to be helpless without Megan, and the G3 ponies had virtually no conflict to begin with.
The male fans of the show seem to like it this way too, to the point that if someone refers to the main characters as the "Mane 7" and includes poor Spike, it tends to cause drama.
Not to mention the famous Dahomey Amazons, or Mino, who composed a third of the Dahomeyan Army in the 19th Century. Fanatically dedicated and intensively trained, they were nearly unbeatable for three and a half centuries, until the invention of the machine gun made industry more important in war than bravery.
If we're counting nonhumans, honeybees. The nonbreeding female workers sacrifice their lives with a sting, so that the vital queen and her male consorts can survive.
Some aphids have a similar system to bees, in which a single female aphid gives birth to dozens of clones of herself. While a few later produce sons and breed sexually, the majority of the clones are cannon fodder: either actively fending off predators from the colony, or just surrounding the breeders so they'll be eaten in their stead.
Also, spotted hyenas are Nature's version of this trope.
There were three all-female combat Soviet Air Force units in World War II, which together flew a total of 30,000 combat sorties, produced 30 Heroes of the Soviet Union (the highest honour available) and 2 fighter aces (the only recorded female aces in history). The most famous of these was the 588th Night Bomber Regiment, nicknamed the Night Witches by the Germans. Not only did they fly over 23,000 sorties and is said to have dropped 3,000 tons of bombs, it was also the most highly-decorated unit in the Soviet Air Force at the time, receiving 23 Heroes of the Soviet Union awards. Not only that, they flew horrifically out of date, wood and canvas bi-plane bombers originally constructed for training and crop dusting - and these planes proved excellently suited for precision night bombing, the reason this regiment was called Night Witches. Weak engine means a quiet engine, plane designed for trainees must have a low stalling speed, reducing noise even more, and low speed gives you an excellent bombing accuracy.
The Soviets also fielded several all-female anti-aircraft regiments. Most of these, however, were completely wiped out when deployed against infantry in the Red Army's desperate attempts to stall the German advance.
There were also numerous female Soviet snipers (one, Lyudmila Pavlicenko got 309 confirmed kills before being pulled off the front line and used for propaganda purposes), and occasionally tank crews. Let's also not forget the Israeli armed forces. However, both are cases of desperation in a way; the Soviets mobilized almost totally to repel the Germans, while the Israelis are surrounded by hostile neighbors, against whom they have a demographic disadvantage, having a smaller population and significantly lower birthrate; it's also a heavy-militarized country in general. (Fun fact: If China maintained an armored corps that had the same ratio to the size of the general population as Israel, it would have more than a million tanks.)
Lyudmila Pavlicenko was so awesome that Woody Guthrie actually wrote a song about her shooting Germans, she was that cool.
During World War I there was a battalion made up entirely of women, led by a woman named Maria Bochkareva, who personally petitioned the Czar to be allowed to serve in the Russian Army to escape her abusive husband. Towards the end of the war, she was put in charge of the Women's Battalion of Death. It was something of a publicity stunt to try and raise morale in the Russian Army. It failed, and about eight months after they were formed Lenin overthrew the Russian Provincial Government and the rest is history.
During the Russo-Japanese War there was an all-woman cavalry regement. The officers were daughters of the country nobility who from hunting could ride and shoot as well as their brothers; the enlisted women were recruited from a Central Asian tribe with a strong Amazonian tradition.
The United States Marine Corps developed the "Lioness Program" for use in Iraq and Afghanistan. Lioness is an all-female team meant to conduct culturally-sensitive searches, but in practice have done much more. The Lionesses have proven extremely useful for building rapport with the locals and gathering intelligence. (And should it come to that, "Every Marine is a Rifleman," even if she's not a man.)
Women in ancient Iranian cultures, such as the Scythians, the Sarmatians, and even the Persians, frequently fought alongside the men. Archaeologists have found many tombs where women received a warrior's burial.
The Women Guard of the Reds in the Finnish Civil War 1918. Inspiring both awe and admiration on the White side (some Whites compared them as "she-wolves" while others as "Northern Amazons" as they managed to repulse a German assault unit in combat), they nevertheless inspired the victorious Whites to found the Lotta Svärd women's army auxiliary organization. Women were finally allowed to serve in all branches of the armed forces in 1992.
Sun Tzu earned his reputation by forming one, allegedly. Before he was a famed strategist, he was tasked to turn 180 concubines into soldiers.
During the Franco-Prussian War of 1870-1871, the feminist and socialist leader Louise Michel organized a women's complement to the Eighteenth Arrondissement Vigilance Committee, essentially a citizen militia to defend Paris.
