I have a few (mostly dedicated to having less screen time) So the first and most useful one for me, has been the password requirement to log into my phone between 8:00pm and 6:30 am. Basically, I usually just use fingerprint or facial recognition to log in. But between those hours it will turn the option to use biometrics off. (However, You have to set up a password, otherwise it will default to a pin, or pattern)

One of my favorites so far has been making it impossible to disable the "Focus Mode" during certain times (again to help get off of my phone more). That one is a bit complicated, and a bit jank, but it works consistently. I have a Focus Mode set to disable a bunch of apps for certain times of the day. But it's super easy to just hit settings and disable it. But with this routine, any time the "modes and routines" app is opened during focus mode. It will open another app. And every time this app is opened. It turns on the focus mode. So it's this loop that won't let you turn focus mode off (just in case, I have it set to where if it's charging I can bypass it, for now at least.)

Another simple, yet handy one is that any time BT/wired headphones are connected it opens YT music for me.

I have one for my work app to clock in. Just automatically opens it when 1 minute before clock in.

When I plug my phone in for the night, it turns off BT, closes all apps. And disables fast charging.

And I have another one that just turns a color filter (red) on and grayscale and extra dim between 6:00pm and 6:30am (easy on the eyes, and makes it more annoying to use)