I'm not sure if there is a sculpt brush folder exactly. If you want to add brushes to your current or new blend they can be appended just like the materials for the skin blend you also just asked about.

Might I also suggest this add-on:

https://www.blendernation.com/2015/02/17/free-blender-brushes/

It adds 14 brushes, and a tab with a more streamlined interface for sculpting. It also then does add a folder in the addons folder for "sculpt_brushes". This might help you. (See image below.)

I'm not sure what version of Blender you are using, but this add-on does work correctly for me in 2.79. Looking at the comments on that page, some people with other versions of Blender have apparently had issues with the add-on. If it doesn't work for you, the comments might provide some help.

Let me know if you have any questions.

Eric, Erock3D