This is my Favorite DIY Smart Switch. It’s tiny, it has 2 relays, and all the extra GPIO pins are available for adding capacitive touch modules, temperature sensors, motion sensors, or pretty much anything else. The firmware it comes with is great, and allows for local-only control, or it’s easy to replace it with TASMOTA or a custom ESPhome sketch (which is what I’ve done with mine).
The BH OnOfre project is an IoT solution based on ESP8266 with the aim of making home automation much simpler, in an open and unrestricted manner. All source code is open as well as hardware.
BH OnOfre Easy Light is a device based on ESP8266 with 2 solid state relays each of 2A, this allows to control up to 2 independent lighting circuits. The fact that it has solid state relays allows you to switch lights on and off silently. OnOfre can be installed behind normal switches, has connectors to turn on the normal switch, or touch sensor. In addition to the dedicated connectors, it also allows you to connect the most diverse sensors / actuators to the available GPIO’s. The control can be carried out via Web, MQTT or manually by the switch, it has automatic integration with the Home Assistant. More info at Easy Light REPO