u/BitApprehensive5041

I'm planning to write a comprehensive, well-organized math reference book, based on the stuff taught in math classes. I initially wanted to use Khan Academy, but for lower level classes, information on a lot of topics is scattered between multiple different units in different courses, meaning it takes a lot of work to combine different units into single sections. Does anyone know a different online resource that organizes things better?

I want to make a reference book for math, containing everything Khan Academy has on algebra, calculus, statistics and probability, linear algebra, and differential equations. I want it to be as comprehensive as possible. A problem is that Khan Academy has redundant courses algebra, statistics, and calculus, and it isn't clear whether the courses on the same topic always contain slightly different things. To me, Algebra 1 and 2 seem better for algebra than Algebra Basics and College Algebra, and Differential and Integral Calculus seem better organized, though I haven't officially tried all of them yet. The choice between AP/College Statistics seems less clear. Does anyone know for sure which of these are more comprehensiive?