Arun Basil Lal

A simple plugin that lets you add your custom CSS to style the WordPress Admin. Works with WordPress single install and WordPress multisites.
Version 2.0 is updated wtih an Admin interface and can be found in Appearance > Admin CSS MU
Admin CSS MU uses CSSTidy to clean and optionally minify CSS. CSS is only minified while using it. The editor always shows un-minified CSS for easy editing.
Note: If you want to easily add custom CSS on your Login and Front-end as well (along with WordPress Admin), use my <a href="https://wordpress.org/plugins/custom-login-admin-front-end-css-with-multisite-support/" rel="ugc">Custom Login Admin Front-end CSS</a> plugin instead.

Admin CSS MU

Good plugin

Add custom CSS to style the WordPress Admin. Works with Multisites.

kontur.us

Simply stop the abusive admin nags from All in One SEO plugin and as well from YOAST Seo! Plus: Add your own CSS to the Admin Area.
<h3>Stopping the Admin Premium Ads for free</h3>
This simple Plugin, will clean most of the abusive admin Spam from the “All in One SEO” – Plugin. And NOW as well from the “YOAST SEO Plugin” 
AIOSEO ist a great plugin, and we love it. BUT it is enough to mention it once that there are premium versions. 
And there IS NO REASON to block functions, like e.g. the editing of Category Descriptions. 
So this will clean things a little for us.
<h3>What the plugin does</h3>
<ol>
<li>Clean the wp-admin bar from advertising AND useless links to functions that are not free, and therefor utterly useless links</li>
<li>Clean the AIOSEO set up pages or Yoast SEO pages from premium advertising and tabs that lead to useless settings, which are not available in the free version</li>
<li>Get rid of the strange ad on the category page</li>
<li>Clean the page / post editor screen from numerous premium ads that make the editor almost looking like an advertising board</li>
<li>Option to load your own CSS into the WP Admin Area. The cutom admin CSS input runs with CodeMirror for an easier handling of the CSS input ( line numbers, color highlight, autocomplete). </li>
</ol>
<blockquote>
Important: If you see new spam, PLEASE let us know! 
 We do write updates once we know, that new spam occurs!
Note: 
 The version after 2.7 does now work as well with YOAST SEO.
</blockquote>
<h3>Add your custom css, to clean even more</h3>
You can add your own CSS to block other nags on the settings page. We intend to develop this part further with snippets for the most annoying plugin naggers out there.
<blockquote>
If you like that approach, 
 please get involved and send uns your snippets. Via email or on the WordPress support page 🙂
</blockquote>

NO admin premium NAGS

Simply stop the abusive admin nags from All in One SEO plugin and as well from YOAST Seo! Plus: Add your own CSS to the Admin Area.

Admin CSS MU vs NO admin premium NAGS