Activity Book (not yet complete)
Free online textbooks: OpenStax, Active Calculus by Boelkins, Contemporary Calculus by Hoffman, Elementary Calculus: An Infinitesimal Approach by Keisler, Calculus in Context (science-oriented)
Videos: Essence of Calculus series by 3blue1brown, Calculus Videos Project, James Tanton
Study tips from Psychology Today
Math Anxiety: What's happening?, Math Relax (soundtrack & video)