Themes allow you to change the look and feel of your Drupal site. You can use themes contributed by others or create your own to share with the community. Contributed themes are not part of any official release and may not have optimized code/functionality for your purposes.
You can also create a sub-theme of an existing theme. A sub-theme inherits a parent theme's resources. Read more about Sub-theme structure and inheritance.
You can also view a full index of themes listing only their titles.
Amazing responsive is a very modern and professional Drupal 7 theme giving your endless possibilities. It has a very clean, minimal and elegant design perfect for any kind of site, portfolio or blog site.
Bytorg is an advanced Drupal 7 theme by Oleg Padalko, with dark colors and flash banner. It is designed as an Ubercart e-commerce theme that is easy to customize, but is extremely flexible for any type of site.