jorgecasar

If you have the capacity of “edit_themes” you can see a Try Theme, a new option in Design menu.
In this page you see a form that let you choose a theme and it will be activated while you’re login in.

Try theme to develop

This plugin detect if current user have the capacity of "edit_themes" and then he can change the template to develop it.

fightthecurrent

Adding shortcodes to the Visual Editor can be a pain in the buttocks. Not anymore. 
Now, you can add shortcodes and a button to the editor as simply as using an 
array and this plugin. <a href="http://bit.ly/Pvj4ie" rel="nofollow ugc">How neat is that?</a>
You can check out more details on how to use the plugin, please visit <a href="http://fightthecurrent.org/plugins/shortcodes-generator" rel="nofollow ugc">the plugin site.</a>
Note: This plugin requires at LEAST PHP 5.3. If you’re not sure what version of PHP you’re using, consult your host.
<h3>Credits</h3>
Some icons by <a href="http://p.yusukekamiyamane.com/" rel="nofollow ugc">Yusuke Kamiyamane</a>. All rights reserved. Licensed under a <a href="//creativecommons.org/licenses/by/3.0/" rel="nofollow ugc">Creative Commons Attribution 3.0 License</a>.

Shortcodes Generator

A plugin to generate shortcodes and a corresponding button in the WordPress visual editor. Wicked!

Try theme to develop vs Shortcodes Generator