Borrowed from Reddit, I may go back and add links to make it easy to find them on Amazon.
The List:
Toddler/Nursery School
In the Night Kitchen, by Maurice Sendak; Reasons: nudity
The Family Book, by Todd Parr; (Reasons: homosexuality, racially-mixed families)
My Mom's Having A Baby! A Kid's Month-by-Month Guide to Pregnancy, by Dori Hillestad
Butler; Reasons: nudity; sex education; sexually explicit; unsuited to age group
Everyone Poops, by Taro Gomi; (Reasons: obscenity, misleading illustrations)
Pre-K
King & King, by Linda de Haan; Reason: homosexuality
My Princess Boy, by Cheryl Kilodavis; (Reason: homosexuality, gender line blurring)
Draw Me A Star, by Eric Carle; Reason: nudity
Bumbe-Ardy, by Maurice Sendak; (Reason: death, too sad for children)
Where the Wild Things Are, by Maurice Sendak; Reason: witchcraft, supernatural elements
K
And Tango Makes Three, Peter Parnell and Justin Richardson; Reason: homosexuality, religious viewpoint, and unsuited to age group
The Pain and the Great One, Judy Blume; (Reason: animosity between siblings)
A Light in the Attic, Shel Silverstein; Reason: unsuited to age group, inappropriate subject matter
The Rabbits' Wedding, Garth Williams; Reason: interracial marriage
The Story About Ping, Marjorie Flack; (Reason: spanking)
Sylvester and the Magic Pebble, William Steig; Reason: police officers depicted as pigs
Early Elementary
The Magic Tree House, series, Mary Pope Osborne; (Reason: encourages dishonesty)
Harry Potter, J.K. Rowling; Reasons: anti-family, occult/Satanism, religious viewpoint, violence
Bridge to Terabithia, Katherine Paterson; Reasons: occult/Satanism, offensive language, violence
Tales of a Fourth Grade Nothing, Judy Blume; (Reasons: child lacks discipline, bad parenting)
Freckle Juice, Judy Blume; (Reasons: bad parenting)
The Boxcar Children, series, Gertrude Chandler Warner; (Reason: anti-family, depictions of criminal activities)
The Witches, Roald Dahl; Reason: unsuited to age group, occult
Blubber, Judy Blume; Reason: Bullying
James and the Giant Peach, Roald Dahl; Reason: violence, occult, anti-family, language
The Giving Tree, Shel Silverstein; Reason: unsuited to age group
Late Elementary
The Boy Who Lost His Face, Louis Sachar; (Reason: bullying, occult)
The Great Gilly Hopkins, Katherine Patterson; Reason: anti-family, unsuited to age group
The Giver, Lois Lowry; Reasons: violence, unsuited to age group
Flashcards of My Life, Charise Mericle Harper; Reasons: sexually explicit and unsuited to age group
The Golden Compass, His Dark Materials series, Philip Pullman; Reason: religious viewpoint
The Upstairs Room, by Johanna Reiss; Reason: inappropriate language, depictions of war
Olive's Ocean, by Kevin Henkes; Reasons: offensive language, sexually explicit
Blood and Chocolate, by Annette Curtis Klause; Reasons: sexually explicit, unsuited to age group (Note: I read this in elementary school, but it is likely better suited to late middle school at the earliest)
Captain Underpants, series, by Dav Pilkey; Reasons: offensive language, unsuited to age group
Number the Stars, Lois Lowry; (Reasons: setting, inappropriate to age group)
Julie of the Wolves, by Jean Craighead George; Reasons: unsuited to age group, violence
Island of the Blue Dolphins, by Scott O’Dell; (Reasons: anti-family, violence)
Are You There God? It's Me, Margaret, by Judy Blume; (Reasons: puberty)
Crazy Lady!, by Jane Leslie Conly; Reason: offensive language
Scary Stories (series), by Alvin Schwartz; Reasons: insensitivity, occult/Satanism, unsuited to age group
Athletic Shorts, by Chris Crutcher; Reasons: homosexuality and offensive language
Goosebumps (series), by R.L. Stine; Reasons: violence, occult, satanic themes
Middle School
Fat Kid Rules the World, by K.L. Going; Reason: depression, suicidal thoughts
Earth’s Children (series), by Jean M. Auel; Reason: violence, anti-family, (scientific inaccuracies)
Whale Talk, by Chris Crutcher; Reasons: racism, offensive language
The Lord of the Rings, by J.R.R. Tolkien; (Reasons: satanic themes)
The Chocolate War, by Robert Cormier; Reasons: offensive language, sexually explicit, unsuited to age
Go Ask Alice, by Anonymous; Reasons: drugs, offensive language, sexually explicit
Fallen Angels, by Walter Dean Myers; Reason: offensive language
Taming the Star Runner, by S.E. Hinton; Reason: offensive language
13: Thirteen Stories That Capture the Agony and Ecstasy of Being Thirteen, by James Howe, ed.; (Reason: unsuited to age group)
ttyl, Internet Girls series, by Lauren Myracle; Reasons: offensive language, sexually explicit, unsuited to age group
The Hunger Games, by Suzanne Collins (late middle school); Reasons: sexually explicit, unsuited to age group, and violence
My Brother Sam is Dead, by James Lincoln Collier and Christopher Collier; (Reason: violence, depictions of war)
Thirteen Reasons Why, by Jay Asher; Reasons: Drugs/alcohol/smoking, sexually explicit, suicide, unsuited for age group
Detour for Emmy, by Marilyn Reynolds; Reason: sexual content
A Day No Pigs Would Die, by Robert Newton Peck; Reason: violence, girl, (explicit descriptions of animal mating behaviors)
The Adventures of Huckleberry Finn, Mark Twain; Reason: offensive language
The Absolutely True Diary of a Part-Time Indian, by Sherman Alexie; Reasons: offensive language, racism, sex education, unsuited to age group, and violence
Early High School
To Kill A Mockingbird, by Harper Lee; Reasons: offensive language, racism, unsuited to age group
Bless Me, Ultima, by Rudolfo Anaya; Reasons: occult/satanism, offensive language, sexually explicit, and violence
The Color Purple, by Alice Walker; Reasons: homosexuality, offensive language, sexually explicit
Forever, by Judy Blume; Reasons: offensive language, sexual content
The Fault in Our Stars, by John Green; (Reason: depression, too “deep” for age group)
The Perks of Being a Wallflower, by Stephen Chbosky; Reasons: homosexuality, offensive language, sexually explicit
Summer of My German Soldier, by Bette Greene; Reasons: offensive language, racism, sexually explicit
Crank, by Ellen Hopkins; Reasons: drugs, offensive language, and sexually explicit
I Know Why the Caged Bird Sings, by Maya Angelou; Reasons: offensive language, sexually explicit
Beloved, by Toni Morrison; Reasons: offensive language, sexually explicit, and unsuited to age group
Tweak: Growing Up on Methamphetamines, by Nic Sheff; (Reasons: drug use, unsuited to age group)
We All Fall Down, by Robert Cormier; Reason: offensive language, sexual content
Lush, series, by Natasha Friend; Reasons: drugs, offensive language, sexually explicit, and unsuited to age group
The Color of Earth (series), by Kim Dong Hwa; Reasons: nudity; sex education; sexually explicit; unsuited to age group
Looking for Alaska, by John Green; Reasons: Offensive language, sexually explicit, unsuited for age group
Late High School
My Sister's Keeper, by Jodi Picoult; Reasons: homosexuality, offensive language, religious viewpoint, sexism, sexually explicit, unsuited to age group, violence
The Kite Runner, by Khaled Hosseini; Reasons: offensive language, sexually explicit, and unsuited to age group
What My Mother Doesn't Know, by Sonya Sones; Reasons: sexism, sexually explicit, and unsuited to age group
Nickel and Dimed, by Barbara Ehrenreich; Reasons: drugs, inaccurate, offensive language, political viewpoint, and religious viewpoint
Revolutionary Voices, edited by Amy Sonnie; Reasons: homosexuality and sexually explicit
The Catcher in the Rye, by J. D. Salinger; Reasons: sexual content, offensive language, unsuited to age group
The Glass Castle, by Jeanette Walls; Reasons: Offensive language, sexually explicit
I hope you enjoy!