MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Vimcal - Vimcal is the world’s fastest calendar, beautifully designed for people who work remotely and live in their calendars.
SendOut - Affordable email marketing for bloggers and influencers
Add-to-Calendar Button Generator - This open source projects lets everybody create amazing buttons, where users can add events to their calendars.
rasa.io - Get more from your email list.
Plan - Plan is a better way to organize.