ITRO Popup Plugin
http://wordpress.org/plugins/itro-popup/
http://www.itro.eu/index.php/portfolio/itro-popup-plugin/
Display a popup to your WP site. Age validation for adult-content site. Fully customizable with WP Post Editor. Very easy to use.
Icegram
http://wordpress.org/plugins/icegram/
Popups, header / footer bars, notifications, messengers, Powerful targeting rules, All-in-one, fully integrated WordPress plugin. Compatible with auto responders, other plugins and themes.
YITH Newsletter Popup
https://wordpress.org/plugins/yith-newsletter-popup/
A simple to configure plugin that is really useful for your website. It shows a clean design popup where you can insert images, messages and a newsletter form. Demo »
