ecobee - The smarter wi-fi thermostat
Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
Nest Thermostat (3rd gen) - A slimmer, sharper, sexier thermostat
ioBroker - flexible and modular application for the IoT and Smarthome
Vivint Element Smart Thermostat - A smart wireless thermostat that blends comfort and savings
openHAB - "empowering the smart home" - vendor and technology agnostic open source home automation