Meet the ANAVI Gas Detector: an open source dev board for air quality monitoring in your connected home. It supports MQ-135, MQ-2, MQ-3, and other analog MQ gas sensor modules. It comes with slots for a mini OLED display and up to 3 I²C sensor module.
This gas detector is Arduino IDE compliant. It works with Home Assistant and OpenHAB. You can find out more about it here.