BurnFeed Email Subscription plugin allows you to show Google Feedburner subscription form either as a floating button or in sidebar of your website.

A MailPro API interface to add email addresses into a MailPro address book

Payboard's Intelligent Navigation decreases website bounces, increases engagement, and drives more signups and sales using predictive analytics.

Capture new subscribers. Reward subscribers with custom downloads upon opt-in. Build unlimited lists. Import and export subscribers easily.

e-goi Mail List Builder is a simple plugin to integrate e-goi API with WordPress and manage your newsletter subscribers list!

A simple way for you to email registered users, commenters and subscribers. Automate user growth and revenue with ReadyGraph integration.

This plugin is a newsletter plugin from OdiHost. It can show opt-in form and save user data. You can then send email from your user list, import and export data. There is also email schedule function, where you can set it to send email after a certain day they subscribe. You can read more detail and comment here. Features:

this plugin is for newsletters compaigns.

Easily add a signup form for any of your Contactology Newsletter lists anywhere on your WordPress site.

Renders Signin/Signout forms via shortcodes and handles them

Wakker Media Newsletter Checkout Checkbox adds a newsletter checkbox on the Woocommerce Checkout Page.

This plugin is a simple newsletter plugin. It can show opt-in form, save opt-in email and name, and send emails to your opt-in list. It also have import and export email data ability. You can comment here.

Feedburner Follow Me plugin allows you to show Google Feedburner subscription form either as a floating button or in sidebar of your website.

The Next Mail for WordPress mailchimp. This plugin helps you grow your Mailchimp lists and write better newsletters through various methods. Select form design and setup mailchimp configration. You can create good looking opt-in forms or integrate with any existing form on your site, like your comment, contact or checkout form.