The YITH WooCommerce Stripe plugin let you add a new payment gateway based on Stripe.com
Redirect commenters who just made their first comment to a page of your choice. Allows you to ask them to subscribe, like you on Facebook, etc.
Easily add the Bloglovin' Button to your WordPress blog ...without having to touch any code!
Add newsletter sign up forms to your WordPress site. Subscribers will be saved directly to your MailerLite account. Super easy to set up!
WP FollowMe plugin allows you to add a twitter "Follow me" badge on your wordpress blog.
Widget show subscribe2 bar in any sidebar.
A complete wordpress plugin to send sms with a high capability. Send SMS via WordPress, Subscribe SMS newsletter and Send SMS to Number(s), Subscribes
Easily add a newsletter sign-up form to your Web site or blog, then run email marketing and SMS campaigns with MailUp.
Adds widgets that let you display subscribe links to RSS readers such as Feedly or Bloglines.
ChimpMate is a MailChimp based email marketing plugin. Professional and Custom designs. Includes Lightbox, Slider, Widget, Add-on, Topbar and Flipbox
Based on the well known Subscribe-to-Comments PlugIn, but now with double-opt-in feature to prevent spam.
Build your own completely custom credit card payment forms with Stripe & Gravity Forms!
Add the Mad Mimi webform to your WordPress site! Easy to set up, the Mad Mimi plugin allows your site visitors to subscribe to your email lists.
Add the new comment subscription option to the blog comment form.
Give visitors a strong reason to leave their emails on your website by locking a piece of content behind an attractive opt-in form.
Users can choose to :Receive Comment Reply Notification Only: or :Receive Notification For All New Comments: or :Not Receive Any Notifications:
WP MashSocial Wigdet : A beautiful widget inspired by Mashable to be used in sidebar, it allows you to add your Pinterest, G+ , Twitter , Facebook and
Sidebar widget to easy customize and display your subscribers buttons. All settings are available from Sidebar Widget Admin.
Integrate MailChimp into your e-commerce shop to manage users' subscription directly from your store. WooCommerce 2.5.x compatible.
Relationships are a two-way street. WordPress email can be too.
The best lightbox plugin to display image, video, notify or announcement with very ease and elegant.
Add a list of "Subscribe" links to your sidebar. Options include your blog and podcast feed, Twitter page, iTunes, Facebook Fan Page, Google Profiles
Subscribe Here displays a visible plugin widget in the sidebar with Subscribe by Rss & Subscribe by Email(through Feedburner) options.
Youtube channel subscribe plugin for wordpress
Subscribe to posts within a certain category or categories.
Allows visitors to quickly subscribe to your blog using only an email address
A simple plugin to allow visitors to submit their email and name and be added to the subscribers list
Help your visitors subscribe to your newsletter, and connect with you via your social media profiles.
Subscribe Remind will add a brief message at the bottom of each post inviting users to subscribe to your RSS feed or follow you on Twitter.
Adds a floating follow button (as on WP.COM Blogs) to Jetpack-powered WP.ORG sites.