The Local Bytes Power Monitoring Smart Plug, Preflashed with Tasmota. 

Reminder: This comes pre-flashed with Tasmota. There will be a few steps to connect the device to your home automation system. Read More!  

A favourite for getting started with home automation. Automate anything that can be controlled by turning it off and on.
It even monitors power usage!

Commonly used for lights (Tasmota Configuration)

Note: Compatible Smart Home Hub recommended, but not required, for automation!