Tamora Pierce’s Circle of Magic universe is an excellent example of racial and cultural diversity done well in juvenile and young adult fantasy. The series focuses on four young mages, two of whom are POC, who are brought together to be trained in their unique gifts. All four children have, for various reasons, been orphaned, and form a family of choice composed of themselves and their mentors, at least half of whom are also POC.
The quartet, Circle of Magic, is aimed at middle school readers, with one book focusing on each of the four children. While all four characters are heavily involved in each book, I’m going to focus primarily on Daja and Briar, the two POC main characters.
Daja Kisubo is an ambient metal mage. Pierce describes her as a tall black girl, with hair that she wears in braids. She arrives at Winding Circle Temple doubly outcast: she is part of a travelling merchant people called Traders, and after a shipwreck kills her entire family, the Trader hierarchy casts her out as bad luck for being the lone survivor. As an outcast, she cannot speak to other Traders or even have them acknowledge her existence. At the same time, she faces bigotry and ethnic slurs from other students at Winding Circle Temple. Daja is sent to Discipline Cottage, where she lives with two adult Temple dedicates (Lark and Rosethorn) and three other children who will grow to be her foster-siblings. Daja’s mentor, Frostpine, is a black man who invites her to learn more about her powers, which relate to metal-smithing and forgery.
Daja’s Book is the third in the series, and the plot centers around Daja encountering a Trader caravan and coming to terms with her roots, her exile, and her gifts. I’d say more about her interaction with her people, but it’s a major plot point and I’d rather not spoil it.
Briar Moss is a plant mage. A street urchin and gang member who has never known his parents, he is plucked from the jail where he awaits sentencing for petty thievery and sent to Winding Circle. Briar’s race is more ambiguous than Daja’s; with his black hair, golden-brown skin, and slanted eyes, he is commonly understood to be Vietnamese or Thai descent. For Briar, though, his race is less of an issue than his class: as a kid who grew up on the streets, he has a difficult time adjusting to the wealth and privileges of Winding Circle, and after threatening another student with a knife in response to persistent bullying that went ignored by Temple dedicates, he, too, ends up at Discipline Cottage.
Briar is mentored by Rosethorn, one of the Temple dedicates who runs Discipline Cottage. As a plant mage, Rosethorn teaches him the basics of gardening as well as how to sense and harness the life force in plants. Briar’s Book is the fourth in the series, and Briar must use all the skills he has learned to help Rosethorn find a cure for a new and devastating plague that has emerged.
After the Circle of Magic quartet, there is a second quartet called The Circle Opens, in which each mage travels with their mentor to a far-off land. These books are for a young adult audience, and deal with graphic violence as each mage ends up solving crimes and taking on students of their own. The four protagonists are reunited in a standalone novel, The Will of the Empress. There are then two other novels that focus on Briar’s student Evvy, who is a stone mage and a WOC.
Daja and Briar, however, are far from the only characters of color. There are also well-rounded POC secondary characters, including (but not limited to!) Frostpine, who is Daja’s mentor, and Honored Moonstream, who is the head of Winding Circle Temple. While the race of the children’s two primary caregivers, Lark and Rosethorn, is not given (if I recall correctly? It’s been a while since I reread these books!), they are quite often portrayed by fans as WOC. Lark and Rosethorn are also lovers; this is implicit in the early books but made explicit later in the series. There are also entire cultures and nations of POC that exist within the universe, as well as POC who live alongside white characters in western European-style nations. The universe contains elements of Renaissance Europe, Russia, India, and Southeast Asia, to name just a few.
The books are an exciting vision of a fantasy Renaissance and Early Modern world refreshingly free of tropes and stereotypes about POC that are typically found in fantasy fiction.
Malinda Lo has some suggestions here, N.K. Jemisin has resources here: Describing Characters of Color (an ongoing writing series; parts 1, 2, and 3)and honestly if anyone wants to add some resources for writers feel free to add them.