The Official Themes
ABP Framework provides a complete UI theming system. While you can build your own themes, you can use the following pre-built themes freely in your applications.
The Basic Theme
The Basic Theme is a minimalist theme that doesn't add any styling on top of the plain Bootstrap styles. You can take the Basic Theme as the base theme and build your own theme or styling on top of it. Here, a screenshot from the theme:
The LeptonX Lite Theme
LeptonX Lite is the free version of the LeptonX Theme, which is a part of the ABP Commercial. Here, a screenshot from the theme: