Home Assistant
How to officially get SonOff with default firmware into HA: https://sonoff.tech/product-review/tutorial/how-to-add-your-sonoff-devices-on-home-assistant/, https://github.com/CoolKit-Technologies/ha-addon
How to unofficially get SonOff with default firmware into HA via HACS: https://github.com/AlexxIT/SonoffLAN
How to unofficially get SonOff with default firmware into HA via HACS (seems obsolete): https://github.com/peterbuga/HASS-sonoff-ewelink
How to get Tellstick ZNet loaded with "local plugin" to expose all services via MQTT to Home Assistant: https://github.com/quazzie/tellstick-plugin-mqtt-hass