This is a short list of various stuff I've read related to Improv that I found myself returning to. Either because they were insightful or because they were fun. It's mainly for my own use but I believe that other people can find use for this kind of list
Impro by Keith Johnstone (book).
Websites, Blogs and Resources:
Improv Encyclopedia (website).
Improv does best (website).
Improv Nerd by Jimmey Crane (Blog and Podcast).
NaimMeod (my blog, Hebrew) .
Don't think twice (movie)
Content that is improvised:
Hello from the magic tavern (Podcast)