When considering automation apps for Android, Tasker immediately comes to mind. And although it has name recognition, it's source code is proprietary and the app requires the Google Play store on the device (beyond a 7-day trial version).

So, what FOSS automation apps are there out there?

• Easer by Rui Zhao. Source on Github (449 stars, 1295 commits), F-Droid. Note that there is also a beta version of this app.
• Automation by Jens Schröder. Source on developer's Gitea instance (88 commits), F-Droid.

Other non-free automation apps for Android (not recommended)

• Tasker
• Automate by LlamaLab
• AutomateIt
• MacroDroid
• RuleBot by KF Software House (Hong Kong)