Actively maintained

This is the Bluemarine theme that was included as part of Drupal 6, 5, and 4.7 (and maybe beyond) core. It was removed from Drupal 7 core, but it continues to live on as a contributed theme at this location.

It is a classic table-based, multi-column, recolorable theme that goes against all modern semantic, responsive, etc. design, but works very well as a utilitarian theme. It is good for when what you want is to display information in a neat and clean way, and you don't care too much about whether the display is pretty, frilly, or fancy.