Books
Many of these books are not about screenwriting but I think you may even find them more beneficial than a typical screenwriting book.
Poetics by Aristotle
Aristotle's Poetics for Screenwriters: Storytelling Secrets from the Greatest Mind in Western Civilization by Michael Tierno
Peak: Secrets from the New Science of Expertise by Anders Ericson and Robert Pool
So Good they Can't Ignore You: Why Skills Trump Passion in the Quest for Work You Love by Cal Newport
Mindset: The New Psychology of Success by Carol S. Dweck
Screenplays
Here are a couple links to some of my favorite scripts:
Zootopia, Coco, Soul, Pinocchio
Scriptslug.com has a great script library. Remember these are solely for educational purposes.
video
This might be the most important video on screenwriting on the internet. It delves into the nature of story and breaks down many of the misconceptions or "rules" of narrative structure. Craig Mazin provides a more comprehensive and holistic thematic structure that is generated from our natural storytelling abilities.