The app Find My Device (FMD) is an open source alternative to the proprietary service offered by Google Google Find My Device.

To get help through SMS, send a message with:

fmd [PIN] help

The answer will be:

FindMyDevice Commands:

bluetooth - Toggle Bluetooth on and off
camera - Take a picture
delete - Factory-reset the device
gps - Toggle GPS on and off
locate - Locate the device
lock - Lock the device
nodisturb - Toggle Do Not Disturb on and off
ring - Make the device ring
stats - Get network statistics
help - Show the help