Frenchtastic

This plugin allows you to give your WordPress dashboard a fresh new look. Your admin panel will look clean and will allow you to focus on what’s really important for you and your users. This colours scheme is set as default and the plugin also prevents users from changing it.

Coeur Admin Color Scheme

This plugin allows you to give your Wordpress dashboard a fresh new look.

Senff - a11n

<h4>Summary</h4>
Simple Debug Info Panel for WordPress will enable you to instantly see some “under-the-hood” debugging info for your site. With one click (or none at all), you can see which template is being used, what the post/page ID is, the current screen/viewport size, any categories a post is assigned to, and some more.
Every item’s visibility can be turned on or off, so you have complete control over what will be shown in the infobox.
<h4>Features</h4>
<ul>
<li>Shows template information: see which template is being used for any page you’re looking at.</li>
<li>Shows post/page ID: gives you the internal WordPress ID of the current post/page.</li>
<li>Categories/tags: shows relevant categories and tags of the post/page (if they are not displayed on the page itself).</li>
<li>Screensize indicator: shows the viewport size, updates in real time (so you can figure out why styles within a certain media query are applied or not).</li>
<li>Turn on/off which information you want to see: you can choose whatever you want the infobox to show. </li>
<li>Positioning of box: choose placement of the box from 4 options (top left, top right, bottom left, bottom right)</li>
<li>Default shows or hides: choose whether infobox should be open or closed/minimized by default</li>
<li>Admin Only-mode: make infobox only visible on the front end to users logged in with admin rights.</li>
</ul>

Simple Debug Info Panel

Simple Debug Info Panel shows a little box on your site with helpful debugging info for developers: post/page ID, which template is being used, etc.

Coeur Admin Color Scheme vs Simple Debug Info Panel