User.com is a single workspace providing you with easy-to-use, yet very robust tools for marketing, sales, management, and support teams.

 https://user.com/en/

Multi-channel customer communication tool

Email Marketing: The Definitive Guide

https://backlinko.com/email-marketing-guide
graphically-rich guide to email marketing and marketing automation. Take with a grain of salt, as it may not work for all industries.

Systeme.io is designed for entrepreneurs and small business owners looking to sell their product online with NO Technical Knowledge

https://systeme.io/
Interesting startup that caters to other startups, especially those with non-technical founders.

Ontraport Build a better business Publish. Market. Sell. Organize.

https://ontraport.com/
marketing automation that can do email, sms and postcards