If you fit within the language/runtime restrictions, Cloud Functions and App Engine also both can be invoked with the same scheduler setup. We use Cloud Functio

If you fit within the language/runtime restrictions, Cloud Functions and App Engine also both can be invoked with the same scheduler setup. We use Cloud Functions for monitoring all the time (schedule to call a function once per minute or so that scrapes some metrics from a third party API and pushes to a Prometheus gateway). Costs us something like $0.12/month and has been extremely reliable. We also run apps on App Engine when we can and there all you need to do is add a `cron.yaml` and you can invoke endpoints there easily and practically for free.