Absurdly Youthful Mother: Quite a few of these. Notably, Alicia Foxworth becomes a stepmother to Malcolm (who is a decade or more older than she) at sixteen, and gives birth to her son Christopher at age 17-18; Leigh was thirteen years old when she had Heaven; and Celeste is around fifteen when she gives birth to her daughter.
Abusive Parents: Hoo boy. If you're a V.C. Andrews heroine, you're lucky if your parents/caretakers are only neglectful of you.
Affectionate Nickname: "Angel" for Leigh in the Casteel series, "Butterfly" for Janet in the Orphans series, and "Cat" for Cathy in the Wildflowers series.
Alice Allusion: Lampshaded in the Secrets series, where Karen's daughter is named Alice in the hope that "maybe one day [she'll] fall into a Wonderland" and escape her mother's fate.
Beauty Equals Goodness: The protagonists tend to be very beautiful, with their foils being not really ugly but they have this one particular thing mentioned about them that isn't "beautiful." This is usually being overweight, having bad hair, lips as thin as rubberbands, etc.
Bedlam House: Seems to be an increasingly popular fate for protagonists of the later books
Betty and Veronica: Several examples, most notably the Casteel series (with Logan as Betty and Troy as Veronica to Heaven's Archie) and Landry series (Paul is Betty and Beau is Veronica to Ruby's Archie.)
Bi the Way: Supposedly, April in the Shadows series, although it's pretty much implied after she dates Peter that she is now "straight" again, or at least would not consider another relationship with a woman.
Child by Rape: Corinne was born when Malcolm Foxworth raped his father's wife Alicia, Mal when Malcolm Foxworth raped his wife Olivia, Heaven when Tony Tatterton raped his stepdaughter Leigh, Charlotte when Jed Booth raped his adoptive daughter Lillian, Dawn when Bill Cutler raped his daughter-in-law Laura Sue, Paul when Octavius Tate raped Gabrielle Landry, Linden when Kirby Scott rapes his stepdaughter Grace, and many others.
The Gemini and Heavenstone series both feature a plot involving a main character being drugged and raped so she can conceive a family heir. It's unsuccessful in the former case and successful in the latter.
Christmas Cake: In Garden of Shadows Olivia mentions that at 25 years old she was already considered an old maid. This leads her to rush into marriage with Malcolm Foxworth and convince herself that she is in love with him.
Olivia Gordon of the Logan series marries Samuel Logan mainly to show that she can land a wealthy man like her sister, but also because she is almost too old for marriage (she mentions that it had been commented on and that all her old schoolfriends are now married.)
Daddy's Little Villain: Emily Booth can be considered an example, Corrine could be considered an example, too.
Dark Secret: VC Andrews lived on this trope, there are dark secrets in every book series, multiple secrets in every book.
Death by Childbirth: Leigh, Heaven's mother. Also Gabrielle/Gabriel, Ruby and Giselle's mother. Becomes a plot point in Daughter of Darkness, where Lorelei discovers that she, and her "adoptive" sisters, are really her father's biological children. He impregnates his daughters, and leaves them to die in childbirth, so that the resulting offspring will grow up to lure new victims to him as Lorelei and her sisters have done.
In the Cutler series, Jed passes off his wife's death as dying in childbirth with Charlotte - she actually died from stomach cancer several days previously. This is to hide the fact that Charlotte is actually his adoptive daughter Lillian's baby, the result of him raping her.
In the Cutler series, Lillian's mother, Violet died during childbirth.
Diabolus ex Machina: Happens to Crystal when her adoptive parents are killed in a car crash and she has to return to an orphanage; she even says that it's too much like one of the soap operas her adoptive mother used to watch to be real.
Dirty Old Man: Numerous examples in all books and series, most infamously the Casteel series' Tony Tatterton, who raped his 13-year old stepdaughter Leigh, then later in a fit of dementia/drunkeness, attempted to rape his daughter Heaven (who is the result of Tony's rape of Leigh), and later still, in a similar state, his granddaughter Annie.
Expository Hairstyle Change: Brooke's Important Haircut in the Orphans series. In the Casteel books, Heaven bleaches her hair in an attempt to resemble her dead mother, but then has it dyed back to its natural colour when she discovers that she doesn't need to try to be someone else.
Expy: Stock characters are pretty much the same across several of the series. The heroines, their love interests and their children seem to follow the same kind of mold, with a few deviations. So do the "evil grandmother" figures (Olivia Foxworth, Olivia Logan, Lillian Cutler ...), the "jealous sister" figures (Vera Whitefern, Fanny Casteel, Clara Sue Cutler, Allison Randolph ...), the "vain mother who doesn't care" (Corrine Dollanganger, Jillian Tatterton, Laura Sue Cutler, Haille Logan, Megan Hudson ...) and the "perverted old men" (Tony Tatterton, Octavius Tate, etc).
Geraldine and Howard Carson from the Wildflowers series also bear a more than passing resemblance to Kitty and Cal Dennison from the Casteel series (i.e. "the domineering, fastidious mother who treats her adoptive daughter cruelly because she reminds her that the man she loved had a child with another woman" and "the henpecked father who initially gives his adoptive daughter the love and attention she needs but eventually takes advantage of her sexually").
Family Relationship Switcheroo: Several examples of this. Notably, in the Wildflowers series Cat discovers that Geraldine, her adoptive mother, is actually her sister - they share the same birth mother but Cat was raised as Geraldine's daughter.
Fat and Skinny: It's common for the thin, beautiful heroine to be contrasted with her jealous, overweight foil - Dawn and Clara Sue, Delia and Sophia, etc.
Four Temperament Ensemble: The Orphans series has Butterfly (phlegmatic), Crystal (melancholic), Brooke (sanguine), and Raven (choleric/melancholic); the Wildflowers series Misty (sanguine), Star (choleric), Jade (melancholic), and Cat (phlegmatic). The Shooting Stars series might also have this kind of four-girl ensemble.
Franchise Zombie: To some, the quality of the books declines sharply after the Casteel series, which was the last to be written by Andrews herself. Other readers believe that the books didn't really Jump the Shark (as the Landry series came after the Casteel series but is still one of the most popular series) until after the Logan series.
Freudian Excuse: Olivia Foxworth, Lillian Cutler, and Olivia Logan are given these in the prequels to their respective series that explain why they were so cruel and domineering towards the series' protagonists. Geraldine from the Wildflowers series is also given one through letters that Cat finds in the attic.
The Fundamentalist: Olivia Foxworth, John Amos Jackson, Joel Foxworth, Jed and Emily Booth, Jacob Logan
Generation Xerox: Heaven's daughter Annie and Dawn's daughter Christie are said to look extremely similar to their mothers; so much that some sanity-challenged people keep on mistaking them for their mothers. They even get in relationships similar to the ones their mothers had (Annie in a "forbidden" one with Luke that she compares to her mother's relationship with Troy, Christie with Gavin who comes from the same family that Dawn's husband Jimmy did).
Ghost Memory: subverted in My Sweet Audrina. Audrina's father wants her to gain the memories and talents of her dead older sister of the same name, but the two Audrinas turn out to be the same person.
Hollywood Homely: In-Universe. The young Olivia Foxworth was mocked for being over six feet tall, and believed she was plain, but (according to Corrine) Olivia was considered aristocratically good-looking in society. In the April series, several men seem to find April attractive even though she thinks she is enormously overweight.
Happily Adopted: Very uncommon compared to the alternative, and the few cases of it tend not to last, but Dawn was pretty happy with her adoptive family in spite of them moving around a lot, Crystal probably would have been reasonably happy with her adoptive family if the Diabolus ex Machina hadn't come crashing down on her, and Butterfly does eventually get adopted by a family who genuinely loves and cherishes her. Rain's adoptive mother also gave her more love and attention than her actual mother did, although her home and school life wasn't exactly rosy.
In the Casteel series, Jane and Keith end up being adopted by a wealthy couple who love them dearly and give them a wonderful life. Although they reconcile to some extent with their birth family, they choose to stay with their adoptive parents.
Hypocrite: In spades, often combined with Values Dissonance and Moral Dissonance. The most prudish, uptight, religious characters are often revealed to be abusive (though they justify their abuse in the name of religion), adulterous, dishonest, etc. One of the worst examples of this is in the book Seeds of Yesterday. Narrator Cathy happily engages in an incestuous relationship with her brother, to the point where she blasts anyone who dares to criticize them about it, yet condemns her son Bart and daughter-in-law Melodie for their adulterous affair (Melodie is married to Cathy's other son Jory) and daughter Cindy for sleeping around. Similarly, Bart sleeps with sister-in-law Melodie (and other married women, it's implied) and visits prostitutes, yet constantly verbally and physically abuses Cindy—who is neither cheating on nor related to any of the boys she sleeps with—for her sexual behavior.
I Hate You, Vampire Dad: Daughter of Darkness is based around a teenage girl who comes to resent her father, a vampire, for forcing her and her sisters to lure young men to the house as victims.
In the Blood: Chris and Cathy do things very similar to their own parents.
I Want My Beloved to Be Happy: In Fallen Hearts, it's revealed that Troy faked his death so that Heaven could marry Logan and live happily with him. Also, Paul agrees in All That Glitters to go along with Ruby and Beau's plan to have Ruby take the comatose Giselle's place so that she and Beau can be together, even though he's deeply in love with her and everyone else believes that he and Ruby are married.
Important Haircut: Brooke from the Orphans series cuts her hair when she realizes that she can't live with an adoptive mother who tries to mold her into something she's not (she wants to be an athlete, her mother wants her to be a model).
Love Makes You Crazy: Philip Cutler is the most noteworthy example, going from a well-adjusted guy with an interest in the heroine Dawn to a crazed Yandere who refuses to give up on Dawn when it's revealed that they are actually brother and sister, tries to rape her more than once, marries another woman only to try and turn her into a Replacement Goldfish for Dawn, and even later on tries to do the same thing with Dawn's daughter (and his niece) Christie.
Love Mother, Love Daughter: Bart with Corrine and Cathy may count, Philip with Dawn and Christie. Tony Tatterton takes this further with four generations of women in the same family - he was initially married to Jillian Tatterton but fell for her daughter Leigh, granddaughter Heaven and great-granddaughter Annie.
Luke, I Am Your Father: For one example, Dawn Cutler eventually learns that her father is neither the man who "kidnapped" her in infancy nor Randolph Cutler, who thought he was her father. She was actually the daughter of Randolph's father, who raped his daughter-in-law. Another example is how Heaven's father turns out to be not Luke, but Tony Tatterton, whom she had thought was her grandfather.
Celeste (a name meaning "heavenly") replaces her dead twin brother and believes that she can speak to ghosts and spirits. The Forbidden Sister features a character named Roxanne that became a prostitute.
Momma's Boy: Randolph Cutler, Paul Tate, Malcolm Jr. and Joel get accused of this by Malcolm Sr.
Moral Dissonance: Ruby and Beau's plan in All That Glitters received lots of disapproval from fans. And numerous in-universe examples in Seeds of Yesterday: Catherine and Chris carry on an incestuous relationship, yet blast Bart for his adulterous affair with his sister-in-law Melodie, as well as their daughter Cindy for her promiscuity. Similarly, Bart sleeps with his brother's wife and numerous other married women, yet constantly verbally and physically abuses Cindy for the slightest infraction, not the least of which is being sexually active.
My Beloved Smother: Many, but one especially good example is actually a father: Damian from My Sweet Audrina, who goes to great lengths to preserve the "memory" of his beloved Audrina.
Name's the Same: Olivia Foxworth and Olivia Logan, Laura Sue Cutler and Laura Logan, Catherine "Cathy" Dollanganger and Cathy Carson (though the latter has the nickname of "Cat" to differentiate her) and Catherine Landry, Melodie Richarme-Marquet and Melody Logan, Tony Tatterton and Antonia "Toni" Winters. The heroine of the Early Spring series is named Jordan March, and Family Secrets features a non-related main character also called Jordan March.
Not Blood Siblings: Annie and Luke in the Casteel series, Jimmy and Dawn in the Cutler series, and Rain and Roy in the Hudson series. The Hudson series is possibly a subversion, since Rain marries Austin later on.
Never My Fault: Laura Sue Cutler from the Cutler series, utterly self-absorbed, spineless, and unwilling to take responsibility for her actions. She's either at her vanity mirror or feigning illness to avoid having to take on any sort of responsibility at the hotel.
Oblivious Adoption: Heaven learns early on that Sarah is not her real mother, but doesn't learn until later on that Luke is also not her real father. Dawn also doesn't know that she was 'kidnapped' at infancy, despite her parents and siblings all being tall and dark-haired in contrast to her daintiness and golden hair, until her supposed birth mother dies. Rain also goes for many years without knowing that she's actually biracial and her real mother sold her to a poor black family to keep her existence secret.
Odd Name Out: In the Shooting Stars series, no one bats an eyelid at girls named "Cinnamon", "Honey" and "Ice" ... yet Rose is the one who gets teased for having a weird name!
Inverted in the Wildflowers series where Misty, Star, and Jade tease each other for having such unusual names and Cathy's relatively normal name gets no comment (she gets called "Cat" later on, but it's just an Affectionate Nickname).
Orphanage of Fear: The place where Butterfly, Crystal, Brooke and Raven all meet in the Orphans series. It looks like a good place to live, but...
Parental Neglect: Malcolm neglects his sons, Corrine at first neglects her children, then takes it one step further, Randolph and Laura Sue are too absorbed in other interests to look after their children.
Redemption Equals Life: Of all the "jealous/evil/promiscuous/bitchy sister" characters in the first five series, the only one who doesn't die is Fanny Casteel, the only one of them who eventually somewhat develops into a less selfish person.
In the Delia series, Tia Isabela's Heel Face Turn earns life for her daughter Sophia, who survives a near-fatal drug overdose. Sophia also becomes a much kinder person after this.
Replacement Goldfish: Subverted in My Sweet Audrina; at the beginning the reader is told that the title character is under pressure to replace her dead older sister of the same name, but later finds out she is the "dead girl." Audrina was actually gang raped on her birthday and her parents subsequently wiped her memory and implanted new ones to protect her from the trauma.
Played straight in the Gemini series, where the heroine is forced from early childhood to dress as a male and "become" her twin brother, who died suddenly.
Also played straight twice in the Casteel series. First, when Heaven voluntarily dyes her hair blond, she is mistaken for her mother Leigh by several people, most notably by her father Tony, who raped and impregnated Leigh and eventually tries to do the same to her. Then in the next book her daughter Annie is sent to live with Tony (though she's unaware that he's her grandfather)after she is paralyzed in the car accident that killed her parents. He convinces her to dye her hair blond like the other women and subsequently tries to mold her into his image of Leigh. Much like with her mother Heaven, the resemblance and his worsening dementia cause him to repeatedly confuse her with the other two, to the point where he virtually imprisons her, sabotages her attempts at recovery, and eventually tries to force himself on her late one night.
In the Cutler series, Philip remains so madly obsessed with Dawn, even when he learns that they're brother and sister, that he tries marrying another woman and having her dye her hair blond and wear Dawn's nightgown and perfume to mold her into a substitute for Dawn. And then when Dawn's daughter Christie comes to live with him after her parents' deaths, he begins to confuse her with her mother and eventually rapes her one night.
Retcon: Garden of Shadows retcons many of the events of Flowers in the Attic, although some things are possibly explained by Corrine exaggerating events in her mind or lying to the children.
Similarly, in the Landry series Grandmere Catherine's account of Gabrielle's death differs from Gabrielle's own account in Tarnished Gold. Again can possibly explained by Catherine altering her version of events to comfort herself, since she stated that Gabrielle's last words were to thank her.
Satellite Love Interest: A lot of the heroine's love interests seem to fill this role. Logan Stonewall, Niles Thompson, Paul Tate, Beau Andreas all apply.
Second Love: Austin for Rain, Miguel for Willow, Adan for Delia although he dies and she goes back to Ignacio anyway.
Series Continuity Error: The Dollanganger and Casteel series have this, probably because the prequels were written by a different person.
Settle for Sibling: Beau settles for Giselle when he can't have Ruby in the Landry series.
In the Cutler series, Jed Booth wanted to marry Violet (Lillian's real mother), but had to settle for her sister because polite society dictated he should court the elder daughter.
Sexless Marriage: Subverted with Arden and Audrina. They have sex, but she hates it and merely goes through the motions. Understandable, given that for her entire life, she's been bombarded with stories of her older sister's gang rape and murder and as we later learn, she is the one who was gang-raped as a child. As the marriage progresses, she comes to genuinely enjoy sex. Ruby and Paul's "marriage" was also arranged to be like this, although it also didn't remain sexless forever.
Sibling Yin-Yang: Heaven and Fanny; Dawn and Clara Sue (and to some extent Fern); Ruby and Giselle; Rain and Beri (and later Allison); Olivia and Belinda; April and Brenda.
Spell My Name with an S: Semantha Heavenstone. In the Landry series, Ruby's mother is named as Gabrielle for the first four books but becomes "Gabriel" in Tarnished Gold. In the Dollanganger series, Cathy's mother is named as both Corrine and Corinne.
Spoiled Brat: Corrine, Clara Sue, Allison and Hannah are all examples.
Theme Naming: From the Casteel series to the De Beers series, every main heroine has a name that can be used as a noun: Heaven, Dawn, Ruby, Melody, etc.
Theme Twin Naming: In the Dollanganger series there was Carrie and Cory, and then later, Darren and Deirdre.
The Unfavorite: Vera from My Sweet Audrina, Heaven to Luke and Sarah in the Casteel series, Lillian and later Charlotte to Jed in the Cutler series, Victoria from the Hudson series, and Celeste from the Gemini series.
The Vamp: Yolanda Lange in Petals on the Wind, Vera Whitefern in My Sweet Audrina, Fanny Casteel in the Casteel series, Fern Longchamp in the Cutler series, but especially Midnight Whispers, also Gisselle Dumas in the Landry series. Usually dark-haired and usually after the heroine's man.
Too Good for This Sinful Earth: Leigh "Angel" Casteel, Laura Logan, Gabriel(le) Landry and Eugenia Booth. Also a common fate of the heroines' various love interests (notably Robert Royce and Adan Bovio.)
Traumatic Haircut: A variant in the Dollanganger series: Olivia coats Cathy's long hair in tar to force her to cut it. The children manage to remove the tar with chemicals. Played straight in the movie, where Olivia knocks Cathy out and hacks her hair off. Also, in Celeste, Celeste's mother cuts her hair while she is asleep in order to force her to dress as a boy and "become" Noble.
Unwanted Harem: If you're a V.C. Andrews heroine, every single male who lays eyes on you will want to have sex with you, especially if they're blood-related to you. Consider that Cathy sleeps with her brother (who she marries), her caretaker (who she marries), her dancing partner (who she marries), and her mother's second husband (who she...okay, she doesn't marry this one, but she still professes to love him. In equal measure to all of her other lovers, presumably) in the Dollanganger series, and you'll understand.
Wicked Stepmother: Daphne from the Landry series. Lillian Cutler and Jillian Tatterton could also be examples.
Wife Husbandry: Paul Sheffield's relationship with Cathy has elements of this, though she is already sixteen when he adopts her, and he doesn't appear to have had it in mind at the time of taking in the children. A more straightforward example is Child of Darkness, where the Emersons adopt Celeste because Ami's father-in-law had fallen for her, and wanted to marry her when she was older or at least convince her to have a child, who could become the family's heir. They drug and rape Celeste when it becomes apparent this plan isn't going to work.
Your Cheating Heart: Most notable in the Casteel series, where Heaven and Logan cheat on each other with Troy and Fanny, respectively, and end up giving birth to a daughter and a son who aren't blood-related to each other (although they don't know that at first).