There is also https://www.scriptkit.com/ by John Lindquist which has a great course to get started: https://egghead.io/courses/script-kit-showcase-for-optimizin...
I use Hammerspoon https://www.hammerspoon.org/ What makes it particularly useful is the breadth of coverage of functionality of the API and integration with OS features.
However, I feel like Keyboard Maestro is capable of much more powerful automation of interactions with GUI apps. Steps like Pause until image appears on screen, click on found image, etc… are super handy. The macro editor however leaves a lot to be desired when compared to writing scripts as code.