Calculus with Julia (2019) - Set of notes for learning calculus.
Active preparation for calculus
Open Calculus - Devoted to free calculus resources for students, free and open source materials for instructors, and active engagement for all.
Calculus Made Easy by Silvanus P. Thompson (1914) (HN)
Calculus Explained with pics and gifs (2014) (HN)
Calculus One course (Code)
Introduction to Tensor Calculus
Why Calculus Works - Understanding Calculus through real analysis, complex analysis, and measure theory. (Code)