A Raspberry Pi runs Homegear and homekit2mqtt. It is equipped with two 866MHz radios for Homematic and MAX!.
Additionally an MQTT broker and the homegrown control software (https://gitlab.com/wolutator/dispatcher_ng), which communicates with Homegear, homekit2mqtt, the MQTT433MHz bridge (see below) and other homegrown web clients via MQTT, resists on it.
There is also a DIY MQTT to 433MHz bridge to control Intertechno and other 433MHz plugs (https://gitlab.com/wolutator/Mqtt433Gateway).
An finally a Philips Hue Bridge powered using a PoE adaptor for Philips and IKEA Tradfri bulbs, paired to Homegear.