JB Library Plugin is a powerful site optimization tool for Joomla, which you can use in Joomla 1.5, 2.5 and 3.x. JB Library Plugin allows you to disable Mootools of your Joomla website directly in extension admin. You can also ban other selected JQuery scripts or load it external by libraries, like Google CDN. No conflicts in future, the integrated Javascript Loader load all Javascript files of your website in the correct order. Joomlabamboo adds some other fine features, like a LazyLoad function or a BacktoTop button. JB Library Plugin is free and downloadable on Joomlabamboo's website.

Crosstec's CacheControl gives you the full control about the cache of your Joomla content and extensions. This lightweight Joomla plugin allows you to turn off the cache time on every content of your website. You just define Crosstec's given rules for the cache of a certain page and the cache of this site will be turn off. CacheControl is free and works with Joomla 2.5 and Joomla 3.x.

RokBooser may helps you to speed up your website. This free Joomla optimation extension combines your CSS and Javascript files. RokBooster is also able to convert images or background by Gzip. So the http requests of your website will be reduced. You can download RookBooster on developers website. Its native to Joomla 2.5 and Joomla 3.0.