Bootswatch has some very cool themes for Bootstrap. These are not fully designed website themes how you can find them on other websites, but they give you different stylings for the whole package of CSS elements of the Bootstrap framework (think of buttons, navbars, checkboxes, typography, etc.).
If you are developing a basic website with Bootstrap and want to get rid of the standard bootstrap styling, this is an easy way to apply a good looking theme design to your site by just changing your CSS files. The owner even provides SASS files which allow you to customize them they way you want.
The themes are absolutely free to use and they are built on the latest version of Bootstrap.
