MailPoet - MailPoet is an email newsletter plugin for Wordpress.
HubSpot Free Email Marketing - Powerful drag and drop email marketing in the HubSpot CRM
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Email Marketing: A Beginner's Guide - Master email marketing with these 3 short ebooks from Drip.
ActiveCampaign - Integrated email marketing, marketing automation, and small business CRM. Send beautiful newsletters, setup behavioral based automations, and benefit from sales automation.
GMass - GMass allows you to easily schedule emails, send out mass emails and mail merge campaigns and more with Gmail! Click here to learn about more features!