ifttt - IFTTT puts the internet to work for you. Create simple connections between the products you use every day.
imapsync - Console-based utility for migrating IMAP mailboxes.
Zapier - Connect the apps you use everyday to automate your work and be more productive. 1000+ apps and easy integrations - get started in minutes.
MailStore - MailStore Home - A 100% free single-private-user desktop solution
n8n.io - Free and open fair-code licensed node based Workflow Automation Tool. Easily automate tasks across different services.
audriga Email and Groupware migration - Easily migrate your email, contacts, calendar items and tasks to your new provider or server. No software installation is required.