SmartThings Edge Driver for Wake-on-LAN capabilities.
This runs on your SmartThings hub without any external dependencies.
From the Devices tab in the SmartThings App, click +, Add device and Scan for nearby devices. This will create a single Wake-on-LAN bridge device from which many Wake-on-LAN momentary switch devices may be created.
Use the settings of the Wake-on-LAN bridge device to specify the MAC address (12 hexadecimal numerals) of a target device. This will create create a new Wake-on-LAN momentary switch device that, when pushed, will wake the target device.
If necessary, use the settings of a Wake-on-LAN momentary switch device to set the SecureOn password (12 hexadecimal numerals) required by the target device.
Removing the Wake-on-LAN bridge device will remove all associated Wake-on-LAN momentary switch devices.
For better integration with the SmartThings App and Google Assistant, all Wake-on-LAN momentary switch devices also have an on/off switch capability. When the on/off switch is turned on it behaves exactly as if the momentary switch was pushed (it is automatically reset (turned off) after a moment).
As the Wake-on-LAN protocol only supports waking (turning on) a target device, turning off a Wake-on-LAN (momentary) on/off switch does nothing.
2019 Samsung QLED Q90R TVs cannot be turned on through their native SmartThings integration. This is may be true for other Samsung TVs.
While the native TV thing in the SmartThings App is presented with an on/off switch, turning on the TV here will not work unless it was very recently turned off. When Google Assistant is asked to turn on the TV (through its SmartThings integration) it may complain: “It looks like the TV isn’t available right now”.
A solution is to deploy an instance of a Wake-on-LAN (momentary) on/off switch device that targets the TV.
In Google Home, one can import the Wake-on-LAN (momentary) on/off switch device and the native TV thing from SmartThings. One should give them names so that "Turn on NAME" and "Turn off NAME" voice commands get resolved to both. For example, naming them both "TV" seems to work. Turning on the TV may still result in the “It looks like the TV isn’t available right now” response from the SmartThings native TV thing but the SmartThings Wake-on-LAN (momentary) on/off switch device will still work (the TV will be turned on).