Email Marketing: A Beginner's Guide - Master email marketing with these 3 short ebooks from Drip.
HubSpot Free Email Marketing - Powerful drag and drop email marketing in the HubSpot CRM
Google Sheets Email Marketing - Email automation and validations directly from Google Sheets
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!
Quokka (formerly Kryptowire) - The gold standard in SAST, MAST, IAST, and more!
NEWOLDSTAMP - Email signature generator