As you become more familiar with creating custom functions, you undoubtedly will become more familiar with the built-in native functions available with Sass. We have devoted this entire chapter to common real world examples for using these functions in Sass.
Sass comes with a wide array of already built-in functions that are very powerful and in itself can help with most of the commonly used processes. Sass' function list is quite extensive as illustrated by these categories of function types:
The functions are very well documented on the Sass CSS function reference guide and also outlined in the appendix for your reference.