borantula

Most of the plugins and even standart WordPress tabs in the admin menu are not used very often. 
With this plugin you can make rarely used items in the admin menu invisible until you need them. 
You can just toggle them whenever you need them with Toggle Extra button in the left menu.

Clean WP Admin Menu

Still works!

You can make rarely used items in the admin menu hidden.

wycks

For WordPress 3.8 and above, enhancements to the admin interface which retain most of the core aesthetics of 3.8. It makes the Admin easier to read, especially when you have a lot of menu items.
This admin interface is adjusted for great nation of better reading abilities.
<ul>
<li><a href="https://wordpress.org/plugins/better-admin-reading/screenshots/" rel="ugc">Screenshots</a>.</li>
<li><a href="https://twitter.com/wycks_s/status/415926766130036736" rel="nofollow ugc">Screenshot when used with the admin-color-schemer plugin</a>.</li>
</ul>
Please create any issues or requests on <a href="https://github.com/wycks/WP-Better-Admin-Reading" rel="nofollow ugc">GitHub</a>
Notes:
<ul>
<li>Loads a simple admin only CSS file and adjusts the padding, font-size and seperation of menu items, it also adjusts a few other minor things.</li>
<li>Works with the new admin color schemes, you must hit save after choosing the color theme for the CSS to be applied. This is found under your user settings.</li>
<li>Makes the font smaller for tablets and mobile.</li>
<li>Works with <a href="https://wordpress.org/plugins/admin-color-schemer/" rel="ugc">Admin color schemer</a></li>
</ul>
Some of the CSS code was forked from Admin Interface by Avenue Factory

Better Admin Reading

Restores balance to WordPress 3.8's admin. Improves the admin experience especially if you have a lot of menu items.

Clean WP Admin Menu vs Better Admin Reading