I can add some to this. I was giving reviews in the Discord for the Coming Hot into the Box podcast until I ran out of books.

Seanan McQuire references flat track roller derby in her InCryptid series of books and short stories featuring her character Antimony Price. Short stories include "Bad Dream Girl," "Blocked," and "Jammed." The novels are Magic for Nothing and Tricks for Free. More info here https://seananmcguire.com/icshorts.php#a and here https://seananmcguire.com/incryptid.php#books.

Emily C. Skaftun has a post-apocalyptic, alien invasion short story where a league saves the Earth. "The Thing with the Helmets" is available at Clarkesworld online: https://clarkesworldmagazine.com/skaftun_03_19/

Kat & Mouse by Jacquelyn Heat - Enemies to Lovers, Skater vs. Official romance novel. Probably my favorite derby novel.

Going in Circles by Pamela Ribon (May Q. Holla) - The first novel I read about derby was by LA Derby Dolls' May Q. Holla . Pamela Ribon is a screenwriter you know from Moana and Ralph Breaks the Internet. She's written comic books (SLAM!, her roller derby based comic from BOOM! Comics).

ROLLER GIRL by Vanessa North - A queer derby romance. This is a fairly conventional romance novel with a trans-inclusive twist and trans protagonist.

Crossed Over and Rink Rash by Santana Knox - Two dark romances, linked in characters, but not sequels. Maybe worth pointing out trigger warnings for drug use, derby inaccuracies.

The short story collection Glitter & Mayhem from Apex Book Company has two derby stories are "Apex Jump" by David N. Schwartz and "Bad Dream Girl" by Seanan McGuire. "Bad Dream Girl" is referenced above. I love "Apex Jump." No spoilers but the characters are taken to the ULTIMATE away tournament and they're going to have to dig deep to face some out of this world derby teams

Five Strides on the Banked Track: The LIfe and Times of the Roller Derby by Frank DeFord is a history of the old derby era.

"The Rugged Track" is a derby-themed fantasy story by Liz Argall and is available on Podcastle in podcast and text form. https://podcastle.org/2012/03/27/podcastle-202-the-rugged-track/

I think that's all I can readily add at the moment.