Consider popular Drupal admin themes when creating the styleguide for Backdrop admin.

[klonos]

We did listen to the crowd and have replaced toolbar.module in core with admin_menu. Lets now do the same by taking a look at the most popular themes used as admin/back-end themes in Drupal. What do people like about them compared to Seven? Can we use one of them as a starter and improve it or are we too far ahead with developing our own theme that there's no point? In that case, we can still get some ideas.

Anyways, here's a list of Drupal admin themes (listed by installation count as reported on d.org as of this writing):

• Adminimal / Adminimal Menu
• Rubik
• Shiny (the admin theme used in Commerce Kickstart v2)
• Ember (used in the Spark distribution)

Please feel free to add to the list any admin theme that I might have missed.