Some Wordpress plugins are often updated, which is good think. Plugins that are updated are 100% compatible with last Wordpress version and they also are the most secure possible. A plugin that has not been updated for a long time might not work with last Wordpress version and might create a security breach for you website.
Encode emails to avoid spams. Template to use [@encode@ email="ilove@gmail.com" display="Gmail Lover"]
Automatically add a sliding login/dashboard (or whatever HTML content) to your Wordpress Theme
Live Chat service from ClickDesk is an awesome combo of help desk, voice and video chat and social toolbar for your wordpress website.
Frontdoor Live Chat allows you to chat with visitors to your site via a customizable chat window.
The Original All-in-One Conversion Optimization Suite. Used on over 35,000 sites. See everything your visitors did before they left.
Activate the plugin for smooth scrolling and smooth "back to top" feature.
Header and Footer Scripts plugin enables you to add scripts to WordPress header and footer.