The Zen of Reffing has YouTube videos! https://youtu.be/241NQYHZSsc?si=_Wnfu7x5kJThXaUh
As well as a guide: www.tinyurl.com/zenreffing
Do you learn better by listening to podcasts?
Try Derby from the Balcony:
Derby from the Balcony • A podcast on Spotify for Podcasters
Learn better by trying stuff yourself?
NURDS is a great ref resource to learn pack definition: NURDS: New Ultimate Roller Derby Simulator
Do you learn better by interacting and asking questions?
Roller Derby Rule of the Day
Roller Derby Rules Clarification and Tough Questions
on Facebook is a great resource for continued learning about derby.
There are other Facebook groups for refs and officials of different demographics, including PNW officials, Female and Non-Binary Officials, etc.
Rules Colored Glasses:
This resource is very similar to this one, with lots of resources and links. Created by Adam Smasher. Smasher's page has all the resources I've provided and then some.
https://sites.google.com/view/rulescoloredglasses/