MailChimp - MailChimp is the best way to design, send, and share email newsletters.
HubSpot Free Email Marketing - Powerful drag and drop email marketing in the HubSpot CRM
SendOut - Affordable email marketing for bloggers and influencers
Email Marketing: A Beginner's Guide - Master email marketing with these 3 short ebooks from Drip.
rasa.io - Get more from your email list.
Email Marketing Academy from MailerLite - Learning platform for email marketing expert certification