vSubst is described as 'Creates drive-letters for any folders on your harddisk. Useful to create virtual drives e.g. on laptops'. There are three alternatives to vSubst for Windows. The best alternative is Visual Subst, which is free. Other great apps like vSubst are USBDLM (Freemium) and Extra subst (Paid).
Visual Subst is a small tool that allows you to associate the most accessed directories with virtual drives. It uses the same API similar to the console subst utility, but makes it easier to create and remove virtual drives in a GUI way.
Extra Subst – program designed to make access to frequently used folders of your computer easier. It is also used to create, edit and remove virtual drives of your computer. Extra Subst creates virtual drives on the basis of selected folders.