Bootstrapはデザインが不得意なプログラマの救世主。ありがたや。

Start Bootstrap – Free Bootstrap Themes and Templates
http://startbootstrap.com/

64 Free Bootstrap HTML Templates | TemplateMag
http://www.templatemag.com/free-bootstrap-templates/

Black Tie – Free Handsome Bootstrap Themes
http://blacktie.co/category/themes/

Bootswatch: Free themes for Bootstrap
http://bootswatch.com/

Material Design Lite
http://www.getmdl.io/