Udemy has many free courses, and the following are the one I recommend, and have remained free for a long time:
Katalon Studio is a great piece of software for testing, able to automate tests for APIs and E2E. This course will guide you through the entire process, from installation to enterprise projects.
Continuous integration is becoming more and more important in the world of software, for DevOps, testing and for the developers too. This simple course will introduce you to the current mainstream DevOps tool.
Everybody should learn Excel, not only IT people. Excel is a great office tool and can be used pretty much for everything, calculations, documenting, reporting, etc. This course will show you how to use Excel, in a short, concise way.