Caspar
Caspar Caspar is a simple monochromatic theme with the ability to blend in with most white or grayscale themes. It is incredibly simple yet effective.
Blush
Blush Named for its subtlety and soft colors, Blush will blend in with many themes, especially those with a similar color scheme.
Blue Steel
Blue Steel Blue Steel is a subtle, clean style for your forms. Not only is this style really, really ridiculously good looking, it will fit with many lighter colored themes.