I got a comment on Twitter from a blogger having trouble finding good books with diverse main characters. Here are a few, just off the top of my head, that I have read and loved. This is by no means a comprehensive list:
Nigerian American main character -- a fabulous MG fantasy based on Nigerian folklore and myth.
So great: a reboot of the 1940s comic series that featured the first Chinese-American superhero, re-imagined in graphic novel form by Gene Luen Yang.
I recently reviewed this for the New York Times: middle grade adventure that reboots the Robin Hood myth with a female biracial main character. Awesome.
First fantasy featuring Ash Mistry, British-Indian teen who goes on a thrilling adventure based on Indian mythology.
Featuring a Muslim American teen girl Kamala Khan as a New Jersey superhero who kicks butt and cracks wise. I love this graphic novel series.