Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
Tuya Smart - Tuya Smart is a free to use Lifestyle Application by Tuya Inc.
ioBroker - flexible and modular application for the IoT and Smarthome
Netatmo - Control your heating wherever you are
openHAB - "empowering the smart home" - vendor and technology agnostic open source home automation
Nest Thermostat (3rd gen) - A slimmer, sharper, sexier thermostat