GKauten

Disables a collection of WordPress features that can help your blog run more efficiently and smoother. 
This includes functions such as the auto-save and revision tracking features used on the post and page 
editor sections which can help reduce database size by eliminating the build up of revisions which exist 
purely for administrative purposes and reduce server load. Other functions include the comment author URL, 
WordPress ‘Generator’ tag, and more.
Special thanks to John Blackbourn (http://johnblackbourn.com/) for his explorations of the Core Update system.

WP Feature Disable

Disables a collection of WordPress features that can help your blog run more efficiently and smoother.

TIgor4eg

Easy way to add php code. No need to edit functions.php in your theme directory. 
Just paste code in Admin menu and save. 
Code is highlighted with <a href="http://codepress.sourceforge.net/index.php" rel="nofollow ugc">codepress</a>.

Add Functions

With this plugin you can add new functions through admin menu, without editing your themes functions.php

WP Feature Disable vs Add Functions