ifttt - IFTTT puts the internet to work for you. Create simple connections between the products you use every day.
EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.
Zapier - Connect the apps you use everyday to automate your work and be more productive. 1000+ apps and easy integrations - get started in minutes.
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
n8n.io - Free and open fair-code licensed node based Workflow Automation Tool. Easily automate tasks across different services.
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.