Reddit reviews My Many Colored Days

Another book for your "buy these instead" list - A Family is a Family is a Family just came out last year, and while it features a variety of family structures, the ending is super relevant for foster kids! Here's a review from amazon:

>PreS-Gr 2—A classroom of young children are asked to consider what makes families special. The narrator, a student whose head is hanging low, is nervous about answering, because she feels her family is too different from everyone else's. One by one, the students share, in intricate spreads, what makes their families unique. One student says that her mom and dad keep coming home with more children, another declares that both her moms are terrible singers, another mentions that she lives with her grandmother, and "fair's fair" for a child who stays with her mom one week and her father the next. After listening to all the students, the young narrator recalls a time in the park when her foster mother was asked to point out her real children. Her answer: "Oh, I don't have any imaginary children…. All my children are real." In this warm, nondiscriminating narrative, O'Leary removes limiting definitions and labels like "adopted," "fostered," or "divorced" and instead presents a tale that is innocent and wise. Leng's ink and digitally rendered watercolor illustrations are light and airy and complement the text by capturing the thoughts and purity of a child's perspective. The classroom is a beautiful blend of children of different races, genders, and body types. VERDICT Parents, caregivers, and educators will appreciate the message that this story offers for one-on-one sharing and for discussion with small groups. A sweet and tender tale that shows that families are composed of love regardless of how they may be configured.—Brianne Colombo, Pequannock Township Public Library, NJ

Probably better for the older end of your age range, but couldn't resist mentioning it. Books about feelings in general are good too; my favorites for the toddler/preschool set are The Feelings Book and My Many-Colored Days.

My Many Colored Days by Dr. Seuss