MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Sendy - Sendy is a self hosted newsletter app that sends emails 100x cheaper via Amazon SES
Email Verifier - Email verifier app lets you verify email.
MailerLite - Affordable Email Marketing Software. Get all features (Segmentation, Automation, A/B testing) for up to 1,000 subscribers & send unlimited emails for free!
NoBounce Email List Cleaner - Email list validation & cleaning maximizes the efficiency of your email marketing campaigns and protects your email sender reputation.
GetResponse - Email marketing from GetResponse. Send email newsletters, campaigns, online surveys and follow-up autoresponders. Simple, easy interface. FREE sign up.