We use a ton via Zapier.
1) When a job closes, filter the action by job title, then send an appropriate follow up email asking them to schedule another visit. Massive time saver.
2) When a property is added that's not in our default sales tax area, send an email to the admin team asking them to manually adjust the sales tax setting. This saves time on sync errors when an invoice is generated.
3) This isn't technically an automation, but using job templates with the "Create similar job" function keeps our job titles tidy and allows for much better reporting
This is a fun topic!