MailStore - MailStore Home - A 100% free single-private-user desktop solution
ifttt - IFTTT puts the internet to work for you. Create simple connections between the products you use every day.
MailSteward - MailSteward : The Ultimate E-mail Manager for Mac OS X
Zapier - Connect the apps you use everyday to automate your work and be more productive. 1000+ apps and easy integrations - get started in minutes.
Gmvault - Backup the emails in your Gmail account.
n8n.io - Free and open fair-code licensed node based Workflow Automation Tool. Easily automate tasks across different services.