I am an early childhood special education teacher and behavior analyst (also a parent!).... I recommend:
No More Meltdowns - Jed Baker
+1 for The Explosive Child - Ross Greene
You could look into resources aimed at teaching kids to be more flexible and self-monitor. Unstuck and On Target is used a lot currently (
https://www.unstuckontarget.com/) or search “Zones of Regulation” or “Incredible 5 Point Scale”
Locally, I have heard good things but have not had personal experience with Dr. Dan Shapiro’s parent groups/trainings.
http://www.parentchildjourney.com/journey
Good books for teaching kids strategies: anything by Julia Cook, “Angry Octopus”