Does anyone know of any good resources, books, websites for learning 部首 Bushu (Kanji radicals)?

[Agave9]

I've been using the Kanji Study android app to learn radicals. It's by Chase Colburn. It has flashcard, multiple choice and writing practice.

[Kimiko_Sensei]

Check out WaniKani. I was apart of the Beta when it first came out and its a fun way to learn the building blocks of kanji:

https://www.wanikani.com/

I hope you find this useful.