Looking for a newsletter popup extension similar to this, neat and simple: http://prntscr.com/77jrs0
Here is an advance popup extension that will allow you display newsletter popup throughout the website. You can use static block feature of Magento to create Newsletter signup form, SlideShow, Banners, Text and other type of content. This extension will allow you to call different popups in different pages.
Convert site visitors into customers by triggering custom popup actions. Smart Popup Builder lets you display a popup to visitors who are just entering your site or who are about to leave it. Perfect for collecting email addresses, gathering site feedback, offering coupons, or building a beautifully engaging call to action.
There are, for sure, multiple tools. However, you may check for this Newsletter popup extension. It is as simple and neat as you need. Super easy to manage, with numerous popup themes.
Here are the product page and demo store so you can try: https://www.magesolution.com/popup-for-magento.html
Hope you'll find the solution perfectly suitable for your purpose.
Popup Pro by Aheadworks is a good option for you. It includes a lot of customization options, responsive design, and can be used for some more great purposes, including promo highlights or anything.
Please visit the product page and demo store of the extension:
Hope you'll find the solution sufficient for your needs.