The best alternatives to PigeonBot are MailClark, Alert.email, and SharedInbox. If these 3 options don't work for you, we've listed a few more alternatives below.
SharedInbox for your Teams within Slack - Connect your existing team email (like help@, info@, sales@) to Slack, collaborate over external emails effortlessly!
Vegamail will make your transactional emails look modern and beautiful, with no effort. What's inside? 22 Email templates HTML and MJML format for easy customization Optimized To work with most email clients Modern Feels modern, minimal, and beautiful.
Thunder Mail is an open source, easy to use platform for sending emails at low cost. Send thousands of emails at $0.10 per 1000 emails. Sending email from an application hosted in Amazon EC2, $0 for the first 62,000 emails you send each month, and $0.10 for every 1,000 emails you send after that.