Books:

The Far Right Today, Cas Mudde
Hate in the Homeland, Cynthia Miller-Idriss
Bring the War Home, Kathleen Belew
Inside Organized Racism, Kathleen Blee
American Zealot, Arie Perliger
Extremism, JM Berger
American Swastika, Pete Simi
Going Dark, Julia Ebner
A Lot of People are Saying, Rosenblum and Muirhead
The Anatomy of Fascism, Paxton
Blood and Politics, Zeskind
The True Believer, Eric Hoffer

Podcasts:

Radikaal
American Radical
Behind the Bastards
Boys Like Me
No Compromise
Day X
Straight White American Jesus
Southern Poverty Law Center
American Terror
Trust Me: Cults, Extreme Belief, and Manipulation
Tech Against Terrorism 
Hope Not Hate 
Ballot to Talk About

Bulletins:

Counter Extremism Project's Eye on Extremism
Political Violence at a Glance

Documentaries:

Welcome to Leith
Welcome to the Nazi Village
The Politics of Hate - Picciolini
The Lost Race - The History of the National Front
Louis and the Nazis
Jo Cox: Death of an MP
Generation Hate
Blood in the Face
White Right: Meeting the Enemy
Reconstructing Utøya

Fictional Films:

The Master
American History X
This Is England
Imperium
22 July
Making Of