The Artist's Way by Julia Cameron is a well-known book among once-blocked artists. It has completely changed my relationship with the art making process. Feel free to ask questions about the book or share your own experiences if you have read it.
https://www.amazon.com/Artists-Way-Spiritual-Higher-Creativity/dp/1585421464/ref=sr_1_1?ie=UTF8&qid=1485708938&sr=8-1&keywords=the+artists+way