Candy Candy: At age 12, Candy is "adopted" by the Leagan family to be a companion to eldest daughter Eliza and later ends up as a maid. The children, Eliza and Neal, tease her and order her about, and their mother isn't any nicer.
It later crosses into Rags to Royalty. When Candy gets adopted for real, it's by the Andrees... a clan that's far richer and more uptown than the Legans. In fact, the Legan family is a branch clan to the Andrees and they owe respect to their leaders, Aunt Elroy and Grandfather William, and since William is the one who gave the order to adopt Candy they can't question it. (Though they can be still assholes to Candy behind William's back.)
In Zero no Tsukaima, once Saito becomes Louise's familiar his new life consists of waiting on Louise practically both day and night. This includes washing her laundry and helping her get dressed, among other things. Louise eventually mellows out, more or less, later on.
Victorian Romance Emma: Emma was born in a seaside village where she was given tough jobs and regularly physically and verbally abused. Luckily, she gained a better life after Kelly Stowner took her under her wing and trained her to be a maid.
In Honey Hunt, if the maid is not at home, Yura is often made to wait on her mother and her clients when she comes home after being away at work for so long. Sometimes her mother is even gone for months at a time.
In one story in Pet Shop of Horrors: Tokyo, a young woman who was formerly a hostess from the Philippines ends up Happily Married to a much older man and has a child with him. For some time, she and her son enjoy a life of blissful luxury, until her husband has a stroke and is unable to remember any of his family or care for himself. His other children (who are all as old as the woman is) nearly turn her and her son out, but ultimately keep her as a servant, while considering her child to be inferior because of his mixed nationality. Even when offered a chance to leave though, the woman refuses to abandon her husband. In the end, her husband dies and leaves a note in his will that his dementia was faked and, impressed by the woman's devotion to him, he leaves her one half of his vast estate, with the other half to be divided amongst his other squabbling children.
Ranma ½: Read this manga if you want to see how things would be if Cinderella and her step-family were kunoichi and Cinderella reveals herself a man.
Billy Batson (and his sister, Mary) who would grow up to become Captain Marvel, belonged to a wealthy family but lost his fortune after his parents died and he was sent to an orphanage by his evil Uncle Ebenezer, who actually made a Deal with the Devil to keep his fortune. Despite this, Billy still saves his soul from Satan.
Usagi Yojimbo: Kitsune's backstory. After her mom who really ran the family business died, her "jellyfish" of a father married a mean and shrewish woman (note: not an actual shrew) who spent all their money and eventually convinced him to sell their daughter to an inn.
Jane Eyre's life with her aunt and two snobby cousins wasn't very pleasant but then again, the orphanage she later went to turned out to be no trip to the beach either. But with the fact that she is actually a wealthy heiress and that she gets her happy ending, the trope fits better.
The Baudelaire siblings. They are sent from one Illegal Guardian and useless caretaker to the next, after their parents die in a fire, and their first guardian, Count Olaf, was pretty much the worst of them. It's revealed that he didn't care about them at all and merely wanted their fortune and was trying to kill them to get it. As such, he makes his hatred and hostility towards them quite clear during their time with him. He makes them sleep in one sparsely decorated bedroom together, with a uncomfortable bed, and no crib for Sunny. Also, he usually leaves them a long list of difficult and tedious chores to do, while he's out for the day. He also abuses them.
In the tenth book, "The Slippery Slope", Sunny resides with Count Olaf and his henchmen on top of a snowy mountain after being captured by them. She ends up becoming a servant for the whole group, including cooking meals in freezing temperatures, getting chips out of the car by blowing them out, doing the washing/cleaning, setting and clearing tables, and sleeping in a casserole dish. Keep in mind that she is, at the absolute oldest, two years old during all of this. Snicket himself actually points out the parallel to Cinderella, but tells the reader that this time, replace the name with "Sunny Baudelaire" and cut out the fairy godmother, handsome prince, and happily ever after.
The Fairy Godmother, the first of Mercedes Lackey's Tales of the Five Hundred Kingdoms series, starts out this way. Subverted in that the ambient magic in the land (The Tradition) wants Elena to go to a ball and marry the prince, but the prince is only 11 years old. (Part of the humor and drama of the series is that any number of girls in any given kingdom may be living in Cinderella circumstances, but not all of them can marry a prince.)
Similarly, Lackey's Phoenix and Ashes from her Elemental Masters series has protagonist Eleanor magically bound her to the house so her stepmother can treat her as a slave and use her family fortune.
Chiyo from Memoirs of a Geisha is sold into a life of servitude at a young age and works for the proprietress of geisha house before she is trained to become a Geisha under Mameha.
Harry Potter, before he gets sent off to Hogwarts, and even later on his Uncle Dursley never does stop treating him like crap.
Lampshaded in Half-Blood Prince, though, when Dumbledore visits Privet Drive and spells out to them what terrible guardians they have been.
Then his cousin Dudley reveals he doesn't think Harry is "worthless" at all! The events of the fifth book helped.
Ella Enchanted: It's basically a retelling of "Cinderella" in which Ella's stepmother becomes angry at her for living in her house like a lady when she is actually poor, so when Ella's father Sir Peter is away on business, she turns Ella into a servant.
In A Little Princess, Sara is packed off to a boarding school for formal education. However, after a few years, word comes that her beloved father is dead, and that his fortune is spent. Since Sara can no longer pay for her education, Miss Minchin, the cruel owner of the boarding school, dismisses Sara's maid, confiscates her possessions (except for her doll Emily), moves her into a drafty attic room, and forces Sara to work as a servant. In addition to that, former fellow students like Lavinia start to treat her like she's less than trash.
In Anne of Green Gables, Anne lived with a few stern, bossy foster parents — who were alcoholics, and made her care for six children before she even turned twelve — and this is Anne's account downplaying how bad they were before she moved in with the kinder Marilla and Matthew, who are conservative and stern but also care for her well-being. In Avonlea, her talents and traits are allowed to blossom, which bring her rewards in addition to Matthew and (eventually) Marilla's love.
The Bride in The Song of Songs justifies her dark complexion with this:
Do not stare at me because I am swarthy, because the sun has burned me. My brothers have been angry with me; they charged me with the care of the vineyards: my own vineyard I have not cared for.
Fanny Price of Jane Austen's Mansfield Park was, ironically, sent to live with her rich uncle and aunts because they could logically offer her a better life than her parents could. Her aunt, Mrs. Norris turned out to be a Wicked Stepmother in all but name, and even though her Uncle showed her kindness, Fanny was never allowed to forget that she was a charity case.
The Lottie Project by Jacqueline Wilson, where the heroine writes her school project as the fictional diary of "Lottie", a Victorian girl forced to become a nursemaid in a manor house in order to support her family.
Hetty of the Hetty Feather series is forced into domestic servitude during the book Sapphire Battersea.
The titular heroine of Opal Plumstead has to leave school and work in a sweet factory to support her family after her father is sent to prison.
She had worked ever since she could remember. Never in her life had she gotten to school before noon on Monday, because of the large washings. After the other work was finished she had spent nights and mornings ironing, when she longed to study, seldom finishing before Saturday. Summer brought an endless round of harvesting, canning, drying; winter brought butchering, heaps of sewing, and postponed summer work
Sweet Valley High had a spin-off called Elizabeth in which Elizabeth Wakefield, who has run away to London, has to work as a servant in a manor house because she didn't get the student grant she was expecting and is now stranded with no money. Although there's no stepparent, she is bullied by the young earl's snobby aristocratic fiancée.
In M. M. Kaye's The Ordinary Princess, Princess Amethyst runs away from her home kingdom in order to keep her parents from hiring a dragon as a last-ditch effort to get her married off. She takes a job as a scullery maid in the castle of a neighboring kingdom, and unlike most examples of the trope she's much more satisfied with the job than she ever was as a princess.
In Katie Woodencloak, the stepmother turned Katie out to tend the cows. When she finds that a dun cow is magically helping her, she set out to have the cow killed. Katie ran away, and found a job working in the kitchen.
The Tales from the Crypt episode "Fitting Punishment" is based around a homeless, orphaned teenager being sent to live with his Evil Uncle. The uncle uses the boy as slave labour in his mortuary, verbally and physically abuses him, cripples him during a beating and then murders him because the boy is costing too much money to keep. Eventually the boy returns as a zombie and kills his uncle.
The Korean SeriesShining Inheritance has the female lead kicked out of her home along with her autistic brother by her stepmother after her father apparently dies in a gas explosion.
In another Korean drama series, High Kick Through The Roof, two young girls (one of whom is only 10-11 years old) are forced to go out to work as housemaids after their father runs away and leaves them with no means of financial support.
The Storyteller's "Sapsorrow," based on the fairy tale "Allerleirauh," has its princess run away from her home to become a kitchen servant in the castle of a different kingdom.
In the fifth installment of the Dark Parables series, the character Katherine has this as her backstory. A small side story within the game explains that after their parents' deaths, she and her stepsister Cyrilla were left in the care of an Evil Uncle who forced them to basically work as unpaid domestic servants. This is particularly fitting since Katherine is the title character of the game - The Final Cinderella.
The 1980s version of Pound Puppies has Holly, an orphan who is constantly abused/exploited by her aunt and cousin. By the end of the first season, it was implied she inherited their house, and lived happily ever after. Then came the second season...
In Tom and JerryThe Movie, Robin is being raised by her Evil Aunt while her father's away in Tibet. Said aunt verbally abuses her (she refuses to call her by name, simply calling her "Orphan," and yes, to her face), throws her mother's locket out the window, and is generally only looking after her so she can have access to the fortune Robin is entitled to. It's also implied she locks Robin in her room, and despite the huge amounts of food shown in the kitchen at one point, Robin is never given any.