Deconstructed in the first Artemis Fowl book, when Holly point-blank asks Root if he's harder on her because she's a girl. He admits it, and then points out that she's the first female in Recon, and needs to set an example. It's also worth noting that the only other female up for the job Holly considers a 'bimbo'. The series itself barely averts this trope because of Juliet, Butler's Action Girl sister, though she doesn't do much of anything until book 3.
Isaac Asimov, until he married his second wife, had issues with women due to relations with his beloved Smother. Susan Calvin was the shining exception in the 400+ books he wrote until he was old (in fact, her dealing with the sexism inherent with being the Smurfette of US Robotics was dealt with in a few of the short stories).
In A Brother's Price, the principle is Gender Inverted because men in the series are uncommon due to their fragile health. A boy can feel lucky if his father is still around when he reaches adulthood. Families consist of a group of sisters, the husband they married, and children. Children within a family can have up to thirty girls with only one boy. A family with four boys and twenty-eight girls is considered uncommonly lucky. It is mentioned that, at social meetings, men gather together for the rare opportunity to talk to someone of their own gender.
The Nac Mac Feegle (or Pictsies) have a hundreds-to-one sex ratio, explained by females being rarely born, but are "Queen Bees" (Keldas) who rule over their sprawling, brawling sons, brothers-in-law, and husband. Keldas may, when fully grown, be larger than the males of the species (Big Aggie of the Long Lake Clan, for example).
The Watch books began with a trio of lads, plus Carrot. Sergeant Angua joins the Night Watch as the first w-erewolf. Later on, some of the dwarves start to express the desire to display themselves as female (which is heretical in dwarf culture), so the audience sees a slow growth of female characters in an originally all-male organization.
Monstrous Regiment begins with a Sweet Polly Oliver plot with a girl trying to find her brother who's been lost in the national army. As time goes by, the trope is subverted, because the "boys" she joined up with are slowly revealed to be women. Until the trope is completely inverted, with The Reveal that the only one in the squad that was male was Lt. Blouse.
In Dragon Bones, Stala is, at the same time, the armsmaster and only woman of the Blue Guard, the famous army of castle Hurog where the protagonist lives. It is never mentioned whether she would take women if any applied. She herself is an exceptional woman, who disguised herself as man to get her training, and worked her way up to her present rank.
In Orson Scott Card's Ender's Game, Petra is the only girl ever mentioned at the Battle School; when Ender is first recruited, it is mentioned that girls rarely pass the tests to get in.
Fate/Zero has Saber, a Gender Bender version of a traditionally male character to start with and the only female amongst five individual servants, each summoned by a single master. None of the masters are female.
The Hitchhiker's Guide to the Galaxy series contained only one major female character for the first three books. Douglas Adams explained why he stuck to the Smurfette Principle in an interview; he wasn't comfortable writing female characters because he didn't understand women. He allowed Trillian (instead of Arthur, as he had originally planned) to make the deductive leaps that narrowly prevent a galaxy-wide war. Then was able to avert the Principle in Books four and five by adding Fenchurch and Random, respectively.
In the Jennings series, the setting is a boys' boarding school, reducing the chances of female characters being introduced. Matron is the only female regular character (though an elderly woman, Miss Thorpe, is a minor recurring character).
Kirsty from the Johnny Maxwell Trilogy is the only girl, but does not accept her status, going so far as to call the others 'four token boys'.
Mildly deconstructed in Mistborn: The Original Trilogy. The setting's criminal underworld is heavily male-dominated, and as a result heroine Vin- raised to be a thief by her thief half-brother- has been the only (or one of the only) girl or woman in any given situation for most of her life. This has a very visible influence on her personality.
The Scream: Jesse is the only female member of The Jacob Hamer Band, and Tara the only female member of The Scream.
Tamora Pierce has stated she writes stories with female leads precisely because of Gender Inequality. When she was starting the Circle of Magic series, she saw an article that mentioned that 75% of recently published fantasy books had male heroes, so she inverted the figure by having three girls and one boy as the main characters (a male character with stereotypically "girlie" plant-based magic at that).
Tolkien's Legendarium features very few women, but only rarely follows the actual Smurfette Principle. Tolkien has mentioned that there is only one known dwarf woman in history - Fíli and Kíli's mother, Dís (who is briefly mentioned in The Hobbit and in the appendices to Lord of the Rings). Others certainly exist, but she is the only one he named.
Leah Clearwater in the Twilight series is the sole female werewolf not only in her pack, but in HISTORY.
In Sharon Creech's The Wanderer, Sophie is the only girl among the surly crew of the titular sailboat, made up of her three uncles and two (male) cousins. And they didn't even want to take her in the first place. Their main reasoning was "wouldn't you rather stay at land, where you can take shower every day?".